Antibody Screening and Identification 1 Lecture with Dr. ify.
ฝัง
- เผยแพร่เมื่อ 17 ต.ค. 2022
- we will be discussing antibody detection precisely antibody screening, why we need to do antibody screening and how to do it in this lecture.
#hematology #lecture #education
This is very informative
Nice teaching
Beautiful lecture
Interesting topic!
My Summary
Definition Of “Unexpected” Antibodies: Unexpected antibodies are the type other than ABO antibodies that don't occur normally in the serum of a normal individual. Its occurrence maybe due to blood transfusion or pregnancy, conditions that result in red cell stimulation.
Requirements For Antibody Detection
• Red cellscarry the corresponding antigen must be available.
• The red cells used as screening cells or panel cells should contain both the several known antigens and also low-frequency antigens that are generally present in the population.
• If the panel cells are manufactured commercially, their lot numbers and expiry date must be respected, and the locally prepared panel cells should be appropriately stored, i.e frozen in glycerol.
• Antibodies that exhibit the dosage effect, e.g MM, NN etc must have cells with their antigens present in double dose to enhance their detection.
Reasons For Detection And Identification Of “Unexpected” Antibodies: i) To prevent blood transfusion reactions. ii) To promote monitoring and prevention Haemolytic disease of the newborn.
Methods Used For The Antibody Screening
The patient's is tested against the screening cell set of 2 or 3 cell panels.
Using the column agglutination technology (CAT) or Tube technique.
At Low Ionic Strength Solution (LISS). At 37°C. Using Anti Human Globulin (AHG).
Or using, Indirect Antiglobulin Test (IAT)
It is important to note that Controls be used as they are required to test the avidity of the reagents used, i.e cell.panel.
ANIGRAM: Commercially prepared screening or panel cells come with a sheet that shows a list of antigens present in each vial of the screening set. On the sheet, a positive sign (+) indicates antigens present in each vial, while the negative sign (0) shows the antigens that are absent in each vial. This sheet is called the Anagram.
The Source And Composition Of Screening Cells
The screening cells and panel cells are derived from Blood group O Individuals to avoid any positive result due to ABO antibodies. Also, the screening cells are composed of antigens of all the clinically significant blood systems in a population.
Result
Negative: absence of clinically significant antibody.
Positive: present of an antibody (that is not yet known)
Thank you ma, interesting lecture
Thank you for this wonderful and well-explained lecture.
From this lecture , i understood that;
Antibody detection comprises of two stages:
1. Antibody screening
2. Antibody identification
Antibody screening:
Antibody screening test helps in detection of unexpected antibodies e.g immune IgG, IgM and autoantibodies.
Definition of unexpected antibodies
Unexpected antibodies are antibodies other than ABO antibodies that do no occur normally in the serum of a normal person. They occur as a result of red cell stimulation.
Reason for detection and identification;
It is important to identify them when cross match is incompatible or antibody screening is positive.
Importance of antibody screening
~It helps to detect unexpected antibodies, their clinical importance and to prevent transfusion reactions and to help manage, monitor and prevent haemolytic disease of the newborn.
Method used for antibody screening
Antigram: For an antibody to be identified, red cells carrying the corresponding antigen must be available and this occurs in two forms;
~Screening cells
~Cell panel.
These cells should be prepared from group O individuals to prevent reactions due to ABO antibodies.
The panel of cells can be prepared locally by using cells staff members and stored in glycerol.
Both panel of cells and screening cells contain several known antigens that are generally present in the population as well as low frequency (less known) antigens, and are also commercially available and their expiry dates must be respected.
A sheet showing the list of antigens present in each vial called an antigram comes with the commercially prepared screening cells.
A positive sign shows the antigen present and and negative (0) shows the ones absent.
Any sample with a positive antigen screening should undergo further investigation to identify the antibody responsible for the reaction and to assess the clinical significance of the antibody
Technique
The patient's serum/plasma is tested against 2 or
3 cell set of screening reagents.
Technique used is the column agglutination technology (CAT) or tube technique.
Controls are required which includes: weak anti-D, weak anti-K, weak anti-c, weak anti-fya, weak anti-S
Result:
Negative: absence of clinically significant antibody.
Positive: presence of an antibody.
Thank you ma'am for this lecture.
In summary, Antibody detection refers to an unexpected antibodies that occur as a result of red cell stimulation or antibodies that do not occur normally in the serum of normal individual.
Reasons for this detection is to detect unexpected antibodies in patient's serum and plasma.
In Antibody detection, an alloantibody investigation comprises of two distinct part namely; Stage 1 which is the Antibody screening and Stage 2 which is the Antibody Identification.
During Antibody screening, the cell set of screening reagent must be capable of reacting with all clinical significant antibodies in the patient's sample and also must be group O,must be minimum of 2 individual cells,must not be pooled and must give a antigen expression.
Thank you Ma for this lecture, it was educational.
Unexpected antibodies are antibodies other than the ABO antibodies that do not occur normally in the serum of normal individuals.but as a result of red cell stimulation.
To detect this antibody screening and identification is done
For an antibody to be identified, red cells carrying corresponding antigens must be available and they come in two forms
(1) screening cells (or selectogen)
(2) cells panel.
These cells must be selected from group O individuals to eliminate positive result attributed to ABO antibodies and must not be pooled, they can be prepared locally and commercially. The ones prepared commercially comes with an antigram which is a sheet containing a list of antigens present in each vial of the panel cells. They have lot numbers and expiry date..
The cells panel prepared locally by members of staff is stored frozen in glycerol.
Antibody screening is designed to detect;
Immune IgG antibodies optimally active at 37 degrees Celsius, IgM antibodies which are active at or near 37 degrees Celsius and should be able to detect autoantibodies active at 37 degrees Celsius.
Any sample with a positive antibody screen must undergo further investigation to
Identify the antibody and to assess the clinical significance.
A Patient Serum or plasma is tested against 2 or 3 cell set of screening reagents. The cell set of screening reagents should be capable of reacting with all clinically significant antibodies in patients samples and express all antigens whose corresponding antibody is considered clinically significant in Transfusion Reaction or HDN
Technique:
The patient's plasma is tested against the screening cell set of 2 or 3 cells typically
By column agglutination technology (CAT) or tube technique:
At Low lonic Strength (LISS)
At 37 degrees Celsius
Using Anti Human Globulin (AHG):
At an indirect Antiglobulin Test (IAT)
CONTROLS
Examples of controls required include:
Weak anti-D
Weak anti- K
Weak anti-c
Weak anti-Fya
Weak anti - S
RESULTS
A negative reaction with each (all) screening cells indicates the ABSENCE of any clinically significant antibody in the sample tested while a positive reaction with any screening cell (or all) indicates the PRESENCE of an antibody.
Further test is required to identify the antibody
Thanks ma'am for this wonderful lecture
Thank you ma, for this enlightening lecture.
This video was very helpful as it made me understand the following;
UNEXPECTED ANTIBODIES
Unexpected Abs are Abs that do not occur normally found in the serum of individuals. They occur following stimulation either from blood transfusion or pregnancy. They are looked out for during crossmatch as they may be clinically significant to cause transfusion reactions.
The occurrence of these And ranges from 0.3% to 2.8% of the population, depending on the group of donors or patients studied.
To identify these Abs, screening and panel of cells selected from group O individuals are used. The cells must have Antigens common in the population.
Reasons for Antibody screening and identification include; to detect and identify unexpected antibodies in patient's serum or plasma, to determine the clinical significance of the Abs if detected and to provide compatible blood for transfusion.
Screening detects; immune IgG Abs reacting optimally at 37°C ,IgM Abs active near 37°C and autoantibodies active at 37°C.
During screening, patient's serum or plasma is tested against 2 or 3 set of screening cells also called selectogens.
the cells are gotten from single individuals and not pooled, but at least the minimum of 2 individual cells are tested. The cells must also express all Antigens having clinically significant Abs.
The screening cells are commercially available but can also be prepared locally from individuals within the locality.
Techniques for screening include;column agglutination technology (CAT),Use of LISS, incubation at 37°C, indirect Antiglobulin Test etc.
Controls must be included, which comprise of known weak antibodies such as weak anti-D, weak anti-K, weak anti-c, weak anti-Fya and weak anti-S.
Result
Negative: absence of clinically significant antibody.
Positive: present of an antibody which will be identified with further procedure called Antibody identification.
Thank you ma for this awesome lecture. I have understood that, Antibody screening involves testing patients Serum/plasma against 2 or 3 cell set of screening reagents( cell panel or selectogen).
Unexpected" antibodies
Are antibodies (other than the ABO antibodies) that do not occur normally in the serum of normal individuals. They occur through the stimulation of red cells which from transfusion or pregnancy.
When antibody screening is positive or crossmatch is incompatible, it becomes necessary to identify the "unexpected" antibody so that blood lacking the corresponding antigen would be selected for crossmatch.
The antibody could be clinically significant and needs to be properly screened.
Unexpected red cell alloantibodies can be found in 0.3% to 2.8% of the population, depending upon the group of patients or donors studied and the sensitivity of the antibody detection method used.
For an antibody to be identified, red cells carrying the corresponding antigen must be available.
This comes in two forms: (1) screening cells (or selectogen) and (2) cells panel. They contain several known antigens that are present in the population as well as low frequency antigens. Locally prepared cell panel are stored and frozen in glycerol.
The screening and panel of cells must be selected from group O subjects so that any positive result will not be attributed to ABO antibodies (ant-A, anti-B or anti-AB).
It is important to have cells with some antigens present in double dose e.g.. MM, NN, JK/JK, JK/JK. This is to detect those antibodies that show dosage effect.
ANTIGRAM
It is a sheet that comes with the commercially prepared screening cells or panel cells showing the list of the antigens present in each vial of the screening cells or panel cells
A positive sign is used to indicate the antigens present in the each vial while a negative sign is used to indicate those antigens that are negative in each Vial.
REASONS FOR ANTIBODY SCREENING
• To detect unexpected antibodies in patient's serum/plasma
• To Identify the antibody or antibodies
• defected in serum or plasma antibody screening tests
• To determine the clinical importance of these antibodies
• To ensure availability of compatible units of RBCs for transfusion
For antibody screening, the following things are needed from the patient o carry out antibody screening. They include the followings;
Patient's details such as date of birth, gender, obstetrics history, Ethnic Origin, diagnosis/Clinical Condition/Drugs,Requesting hospital and Clinician, investigations required fully labelled Samples, Screening/ Panel Cells and SOP/Guidelines.
ANTIBODY DETECTION
An alloantibody investigation comprises of two distinct parts
Stage 1; Antibody screening
The screening test is designed to detect;
• Immune IgG antibodies optimally active at 37 degrees Celsius, and IgM antibodies which are active at or near 37 degrees Celsius.
Stage 2: Antibody Identification
Any sample with a positive antibody screen must undergo further investigation. The identification of this antibody becomes a working tool for the assessment of the clinical significance of the antibody identified.
• Must be capable of reacting with all clinically significant antibodies in patients samples.
• Must be group O.
• Must be a minimum of 2 individual cells.
• Not pooled.
• Must give a good antigen expression that is be homozygous.
• Express all antigens whose corresponding antibody is considered clinically significant in Transfusion Reaction or HDN.
TECHNIQUE
The patient's plasma is tested against the screening cell set of 2 or 3 cells typically by column agglutination technology (CAT) or tube technique.
• At Low lonic Strength (LISS)
• At 37 degrees Celsius
• Using Anti Human Globulin (AHG)
• At an indirect Antiglobulin Test (IAT)
Controls
Controls are required and one or more known weak antibodies will be selected. Examples includes
- Weak anti-D, Weak anti- K, Weak anti-c, weak anti-Fya, Weak anti-S.
RESULTS
A negative reaction with each (all) screening cells indicates that clinically significant antibody is absent.
A positive reaction with any screening cell (or all) indicates the presence of an antibody and will require antibody identification.
A negative reaction is characterized by unagglutinated red cells forming a well-delineated pellet at the bottom of the microtube.
A 1+ reaction is characterized by red cell agglutinates predominantly observed in the lower half of the gel column.
Unagglutinated cells form a pellet in the bottom of the microtube.
A 2+ reaction is characterized by red cell agglutinates dispersed throughout the length of a gel column. Few agglutinates may be observed in the bottom of the microtube.
A 3+ reaction is characterized by the majority of red cell agglutinates trapped in the upper half of the gel column.
A 4+ reaction is characterized by a solid band of red cell agglutinates on top of the gel. A few agglutinates may filter into the gel but remain near the predominant band.
A mixed cell reaction is characterized by a band of red cell agglutinates on top of the gel, accompanied by a peller of unagglutinated cells at the bottom of the microtube.
Thank you ma'am for this educative series
Thank you ma, i was able to learn that unexpected antibodies are antibodies other than ABO antibodies that dont occur normally in serum of normal individuals.
** it occurs as as result of cell stimulation through or pregnancy.
Also for antibody to be identified red cells carrying the corresponding antigen must be avaliable . it comes in two forms : 1. screening cells and panel cells
The screening cells and panel cells contains several knowm antigen that are present in population.
The screening and panel cells must be selected from group O
GOAL OF ANTIBODY IDENTIFICATION INCLUDES
To check for unexpected antibodies in patient serum
To determine the clinical importance of antibodies
To ensure avaliablity of compatible unit for RBC transfusion
Thank you Dr, this has helped greatefull to simplify my understanding about antibodies screening and identification,
In summary,I was able to know that every RBC that carries Antibody has a corresponding antigen on it surface,
*Also screening Antibody must be selected from panel cells of group O individuals,I.e any positive result should not be attributed to ABO antibodies
*Antibody screening play a vital role in per_ transfusion testing,
*Nervetheless it has very important role which helps avoid serious and dangerous transfusion reaction,,
Thank you very much ma after the lecture I learnt about unexpected antibodies and the are antibodies other than the abo antibodies and the don’t occur normally in serum of normal individuals and it also can be stimulated through pregnancy and also panel cells
Thank you ma'am for the wonderful lecture on Antibody screening.
I have learnt that Unexpected antibodies are antibodies other than ABO antibodies that do not occur normally in serum of normal individuals.
It occurs due to sensitization in blood transfusion or pregnancy.
When antibodies are screened and detected,it must be identified and it's clinical significance assessed.
Antibody screening is important to:
1) Detect unexpected antibodies in a patient's serum
2) Identify Antibodies detected
3) To determine clinical significant antibodies
4) To ensure compatible units of red blood cells for transfusion.
Antibody screening is important to detect; -Immune igG antibodies active at 37 degree Celsius
-IgM antibodies near or at 37 degree Celsius
-Autoantibodies at 37 degree Celsius and
-To observe potential problems.
In Antibody screening, the technique follows;
1) Patient's serum tested against 2-3 sets of screening reagents.
2)Using column agglutination technology
3) At LISS
4) Test with AHG
5)IAT(indirect antiglobulin test)
The controls used are weak Anti-D,anti-K,anti-c,anti-fya,anti-S.
A positive reaction with any screening cell indicates presence of antibodies while a negative reaction with all screening cells indicates absence of significant antibody.
Thank you
Thank you very much Ma for this lecture, The lecture was very self explanatory, and this is my summary;
Antibody detection occurs in 2 stages
i)Antibody screening
ii)Antibody identification
Antibody screening test helps in the detection of unexpected antibodies.
Unexpected antibodies are antibodies that do not occur normally in the serum of normal individuals and the aim of Antibody screening test is to detect unknown antibodies in a patient’s serum or plasma.For antibodies to be identified, red cells carrying corresponding antigen must be available. These red cells comes in two forms
1)screening cells and;
2)screening panels
Theses screening cells and cell panel could be prepared commercially or locally and stored in a frozen condition. Blood Samples from Group O individuals are used to prepare the cells panel because they do not have A and B antigens on the surface of their red blood cells so that any positive result gotten will not be associated to ABO antibodies
Techniques for Antibody screening test;
The patient’s plasma is tested by column agglutination technique(CAT) or tube technique at a low ionic strength at 37 degree Celsius using AHG.
The controls needed for the test include;
Weak anti D
Weak anti K
Weak anti c
Weak anti Fya
Weak anti S
The importance of this test include;
i) To prevent hemolytic transfusion reaction
ii) To ensure compatibility of units of red blood cells for transfusion.
Results
Positive reaction in one or any of the screening test denotes a positive result, it is important to note that further investigation must be carried out to identify the antibody and assessing the clinical significance
A negative reaction in any or all screening cells denotes the absence of any clinically significant antibody in the sample.
Thank you so much Ma, for the beautiful lecture
I've learnt that antibody detection comprises of two stages:
1. Antibody screening
2. Antibody identification
Antibody screening is used to detect unexpected antibodies in an individual's serum which occur as a result of red cell stimulation. Red cells which are either Screening cells or Panel cells are used for this test. This red cells should contain high and low frequency antigens from the population and they can be gotten commercially or prepared locally from group O blood. Group O blood is used to eliminate ABO antigens. The test detects IgG, IgM or autoantibodies that are optimally active at 37°C. The commercially prepared Screening cells come with an "Antigram" (a sheet which shows the list of the antigens present in each vial of cells). The patient's plasma is tested against 2 or 3 cells set using column agglutination technique, at low ionic strength, at 37°C, using AHG. Agglutination reaction indicates presence of antibodies while no agglutination indicates absence of antibodies
Thank you Dr . your lecture is impactful
What I learned in summary is that screening is done to detect unexpected antibodies which will enable further investigations to be carried out for effective management of transfusion related problems resulting from the reactions of antigens and antibodies.
This utilizes the reaction of known cells with the patients serum.
Antibody detection consist of two stages;
1. Antibody screeing and
2. Antibody identification
Antibody screening uses 2 or 3 screening cells to detect if Antibodies are present in the serum. If antibodies are determined, then they must be identified.
Significance of this is to
1. Detect unexpected antibodies in patients serum/plasma
2. To determine the clinical significant these antibodies.
Unexpected antibodies are antibodies that do not occur normally, they occur as a result of red cells stimulation either via pregnancy or blood transfusion.
For an antibody to be identified, red cells carrying corresponding antigens must be available. This comes in two forms: screening cells and cells panel.
This cells must be selected from group O individually so that any positive result will not be attributed to ABO antibodies. The cells are either locally or commercially prepared. The prepared cells come with an antigram which is a sheet that contains a list of the antigens present in each vial of the screening cells.
Techniques used;
- patient plasma is tested against the screening cell set of 2 or 3 cells typically.
- column agglutination technique(CAT) or tube technique is used
Controls :
Examples of the controls used include
Weak anti-D
Weak anti-K
Weak anti-c
Weak anti-fya
Weak anti-S
Result:
A negative result indicates absence if clinically significant antibody
A positive result indicates presence of antibody.
Thank you ma for this wonderful lecture. I'm really delighted learning this topic from you. Here is what I've learnt below
Antibody detection comprises of two stages
1. Antibody screening
2. Antibody detection
ANTIBODY SCREENING
it helps in detection of unexpected antibodies
- Unexpected antibodies are antibodies other than ABO antibodies that do not occur normally in the serum of normal individuals.
- They can occur as a result of red cell stimulation either through transfusion or pregnancy.
- The known antigens are used to identify the unknown antibodies in a patient serum or plasma.
Red cells carrying the corresponding antigens must be available. They can come in two forms
1. Screening cells(selectogen)
2. cells panel
- The screening cells and panel of cells must be selected from group O subjects so that any positive result will not be attributed to ABO antibodies.
- The screening cells can be procured or prepared locally and stored frozen in glycerol.
- The antigram is a sheet that comes with the commercially prepared screening cells or panel cells showing the list of antigens present in each vial of screening cells or panel cells
- A positive sign is used to show presence of antigen in each vial while a negative sign is used to show absence of antigens in each vial.
REASONS FOR ANTIBODIES SCREENING AND IDENTIFICATION
- To detect unexpected antibodies in patient's serum or plasma
- To identify the antibody or antibodies in the serum
- To determine the clinical importance of the antibodies.
- To ensure availability of compatible units of RBCs for transfusion.
- To prevent blood transfusion reaction
- To prevent HDN
SCREENING PROPER
screening should detect:
- immune igG antibodies active at 37°C
- igM antibodies which are active at 37°C
- autoantibodies active at 37°C
- advance notice of problems
ANTIBODY IDENTIFICATION
any sample with a positive antibody screen must undergo further investigation.
- it should identify an antibody
- it should access the clinical significance of the antibody
- it should determine the titer of antibody
SCREENING PROCEDURES
The screening cells should contain significant antigens like Rhesus, MNSs, P, Lewis, Lutheran, Kell, Duffy, Kids.
The patient's serum is tested against the screening cell set of 2 or 3 cells typically at
- low ionic saline strength
- 37°C
- AHG
- An Indirect Antiglobulin test
A negative reaction indicates absence of antibody
A positive reaction indicates presence of an antibody.
Thank you ma for this detailed lecture.
In summary, unexpected antibodies occur due to stimulation of the red cells either by pregnancy or transfusion. Screening and identification of these antibodies is important to;
1. Detect unexpected antibodies in patient's serum/plasma.
2. Identify the detected antibody(s).
3. To determine their clinical significance.
4. To provide compatible units of RBCs for transfusion.
Antibody detection involves antibody screening and identification. The screening is done with screening cells (selectogen) which has these features...
Comes with an antigram, must be group O from a minimum of two individuals, capable of reacting with clinically significant antibodies and homozygous.
The method for this screening involves testing patient's plasma against 2 or 3 cell set of screening cells using column agglutination technique or tube method at LISS or at 37°C using AHG at an indirect antiglobulin test.
Controls like weak anti- D, weak anti- K, weak anti- c, weak anti- Fya and weak anti- S must be included. Negative result shows unagglutinated red cells( absence of antibodies) while agglutinated red cells( presence of antibodies) is for a positive result.
Thank you for the lecture.
Antibody Detection and screening is carried out to detect unexpected antibodies. ( Unexpected antibodies do not occur normally in an individual's serum, but as a result of red cells stimulation through pregnancy or blood stimulation).
In order to identify an antibody we need;
a. Screening cell/selectogen
b. Cells panel.
A panel cells contains a sheet called ANTIGRAM, which shows the list of antigens present in each vialof the panel cells or screening cells.
The goals of of this testing is to ensure availability of compatible blood units for transfusion and to determine clinical importance of these antibodies.
Antibody screening is carried out in order to prevent blood transfusion reactions and help in the management, monitoring and prevention of HDN.
Antibody Detection occurs In two stages:
A. Antibody screening stage:this helps to detect immune antibodies active at 37 degree Celsius, IgM antibodies and autoantibodies.
B. Antibody identification stage: This is carried preceding an antibody screening, where those showing a position reaction are subjected to further identification to know the specific antibody and access the clinical significance of the antibody.
The control for the screening helps to tests the reagents potency and it's ability to detect weak reactions, this controls comprises of
Weak Anti-D, weak Anti-K, weak Anti-c and others.
Nice one ma
Great video ma, everything was well explained ❤.
Summary
Antibody detection comprises of two stages:
1. Antibody screening
2. Antibody identification
Antibody screening:
Antibody screening test helps in detection of unexpected antibodies e.g immune IgG, IgM and autoantibodies.
Definition of unexpected antibodies
Unexpected antibodies are antibodies other than ABO antibodies that do no occur normally in the serum of a normal person. They occur as a result of red cell stimulation.
Reason for detection and identification
It is important to identify them when cross match is incompatible or antibody screening is positive.
Importance of antibody screening
It helps to detect unexpected antibodies, their clinical importance and to prevent transfusion reactions and to help manage, monitor and prevent haemolytic disease of the newborn.
Method used for antibody screening
For an antibody to be identified, red cells carrying the corresponding antigen must be available. These antigens come in two forms: screening cells and cell panel.
This cells should be prepared from group O individuals to prevent reactions due to ABO antibodies.
A sheet showing the list of antigens present in each vial called an antigram comes with the commercially prepared screening cells.
A positive sign shows the antigen present and negative (0) shows the ones absent.
Any sample with a positive antigen screening should undergo further investigation to identify the antibody responsible for the reaction and to assess the clinical significance of the antibody.
Technique
The patient's serum/plasma is tested against 2 or 3 cell set of screening reagents.
Technique used is the column agglutination technology (CAT) or tube technique.
Controls are required which includes: weak anti-D, weak anti-K, weak anti-c, weak anti-fya, weak anti-S
Result:
Negative: absence of clinically significant antibody.
Positive: presence of an antibody.
Thank so much ma for this wonderful and interesting lecture.
This helped me to understand that unexpected antibodies are antibodies that do not occur normally in normal individuals. It may occur due to RBC stimulation in pregnancy and transfusion.
It is important to detect the unexpected antibody so blood that does not contain corresponding antigen is cross matched for patient , because the antibody may be clinically significant.
Method for antibody screening
Antigram : for an antibody to be identified , red cells carrying the corresponding antigen must be available and this occurs in two forms
A) panel of cells
B) screening of cells
The panel of cells can be prepared locally by using cells staff members and stored in glycerol. Both panel of cells and screening cells contain several known antigens that are generally present in the population as well as low frequency (less known) antigens , and are also commercially available and their expiry dates must be respected.
The screening and panel of cells must be obtained from o group individual so that any positive result will not be attributed to ABO antibodies (anti A , anti B ). It is also important to have cells with some antigens present in double dose i.e NN , MM (MNS) , JKa / JKb( Kidd). This is to detect antibodies that show dosage effect.
Test are carried out at
1)Room temperature to detect cold "complete"antibodies like anti-M , and auto antibodies like anti-H etc
2)At 37° C to detect warm complete antibodiesIg G and (complement binding Ig M and Ig G)
3) Antiglobulin test acts as backup test to detect warm an IgG or complement binding alloantibodies and autoantibodies.
Negetive results with each screening cells indicates the absence of any clinically significant antibody in the sample tested
A positive reaction with any screening cell indicates the presence of an antibody , we can not tell if it's clinically significant in this test , further test is now required to identify the antibody ( Antibody Identification)
Thank you ma, you made the topic easy for me to understand
Thank you ma for this great lecture. I learnt that unexpected antibodies are antibodies other that ABO antibodies that do not occur normally in the serum of normal individuals. They occur as a result of red cell stimulation through transfusion or pregnancy. For an antibody to be identified, red cells carrying the corresponding antigen must be available and they come in two forms
1 Screening cells
2 cells panel
The screening and panel feels must be selected from Group O subjects to avoid results attributed to ABO antibodies.
Goals of antibody screening include detection of unexpected anybodies, to ensure availability of compatible units of RBCs for transfusion.
In antibody detection , an alloantibody investigation comprises of two distinct parts
Stage 1: antibody screening
Stage 2: Antibody identification
Thank you
Thank you ma'am for the lecture.
In summary i've learnt that antibody screening is very important and is done to detect unexpected antibodies.
It is used to manage, monitor and prevent HDN.
It is also used in cross match to prevent transfusion reaction.
The patient plasma is tested against the screening cells. And these cells are from 2 to 3 individual but not pooled.
Thank you ma😊
Thanks so much ma it's well explained and understood!
Wow! I've learned something new and valuable from this topic. Thank you for explaining that compatibility testing involves more than just cross-matching; it's also about detecting and identifying unexpected antibodies. I am Grateful for this knowledge ma.
Thank you sooo much ma..for this great information...
Am really happy I listened...
Ok what I learnt is that for an Antibody to be identified,the redcells carrying the corresponding antigen must be available...
Also this Redcells comes in 2 forms which are
1.screening cells/Celletogen
2.Panel cells
I also understood that the screening and panel cells must be selected from group O individuals so that any positive result won't be attributed to ABO antibodies...
I also got that antibody screening is an important part of pre_transfusion testing because it helps to determine if the patient has an alloantibody because these antibodies are antibodies that are directed against Antigens that are not found in the patient's own blood...
I also learnt that it's important it's done in other to avoid serious and dangerous transfusion reactions ...
TECHNIQUES
1.The use of column agglutination
2.It is done at low ionic strength
3.It is done at 37degree using Antihumanglobulin and Indirect globulin....
Thank you maaaa
Thank you ma for this wonderful series ❤
Well understood ma
Thank you so much ma’am,such an interesting lecture
Thank you very much Ma❤
I now know that these unexpected antibodies After cross match can be identified
Thank you madam.
Thank you very much for the series ma
Thank you ma'am
Thank you very much Ma. This lecture was really educating and explanatory😊.
Here’s my Summary Ma:
Antibody detection consists of two stages:
- Antibody screening
- Antibody identification
Antibody screening uses 2 or 3 screening cells to detect if antibodies are present in the serum. If antibodies are detected, then they must be identified.
Importance of antibody screening and identification:
- to detect unexpected antibodies in patient’s serum/plasma
- to determine the clinical importance of these antibodies
Unexpected antibodies are antibodies that do not occur normally, and they occur as a result of red cell stimulation, either through pregnancy or transfusion.
For an antibody to be identified, red cells carrying corresponding antigen must be available. This cells come in two forms:
- screening cells(also called selectogen)
- cells panel
This cells must be selected from group O individuals so that any positive result will not be attributed to ABO antibodies. This cells can be prepared locally and commercially. The ones prepared commercially come with an Antigram; a sheet that contains a list of the antigens present in each vial of the screening cells.
Technique:
- The patient’s plasma is tested against the screening cell set of 2 or 3 cells typically
- Column agglutination technology(CAT) or tube technique is used
Controls:
Examples of controls required include:
• Weak anti-D
• Weak anti-K
• Weak anti-c
• Weak anti-Fya
• Weak anti-S
Result:
A negative result: absence of clinically significant antibody
A positive result: presence of antibody
Great topic. Keep it up. The atypical antibody detection is key in preventing HTR
Thank you so much Ma for for the wonderful lecture on antibody screening .
In summary, I understood that antibody screening is important to detect;
1. Unexpected antibodies which are are antibodies other than ABO antibodies that do not occur normally in the serum of normal individuals. There are also called irregular antibodies .
2. Antibody screening help in management and monitoring and prevention of hemolytic disease of the new born.
3. It also plays a vital role in blood transfusion, pre transfusion compatibility testing.
Antibody screening test is also designed to detect ;
1. Immune IgG antibodies optimally active at 37 degree Celsius
2. IgM antibodies which are active at or near 37 degree Celsius
3. Should be able to detect autoantibodies active at 37 degree Celsius and allow advance notice of problems such as autoimmune antibody been present in the patient’s sample.
The following are also the techniques for antibody screening
1. Patient serum tested against 2-3 sets of screening reagent
2. Using column agglutination technology
3. At LISS
4. Test with AHG
5. IAT( indirect antiglobulin test)
Controls are also required and the work is to help you test your reagent e.g anti- D, anti-K, anti- c, anti-fya and anti-s.
Positive: presence of an antibody that is not yet known
Negative: absence of clinically significant antibodies.
Lastly, antibody screening also uses 2 or 3 screening cells to detect if antibodies are present in the serum and also if antibodies are detected, they must be identified. Also, any sample with a positive antibody screen must undergo further investigation and this is done to identify the antibody and assess the clinical significant of the antibody.
Antibody screening does not really tell us which antibody is reacting, we need to go a step further to do antibody identification.
Thank you Ma.
Nice lecture
Antibody screening is a test that is performed to detect the presence of antibodies in a person's blood. It's a routine part of blood donation and transfusion medicine, as antibodies can cause complications if they're present in the donor's blood and are given to a recipient. The test involves mixing a small amount of the donor's serum with red blood cells from a panel of different blood types. If antibodies are present, they will cause the red blood cells to agglutinate, or clump together. This provides information about the type of antibodies present and their level of activity.
Thank you Ma, you made it easy to understand
Thank you ma,I understood that blood transfusions play a crucial role in haematology by providing necessary support to patients with blood-related conditions.
Thank you ma😊
From this vivid lecture on antibody screening
I'm able to understand that unexpected antibody are those antibody that are cell stimulated and not naturally occurring. The goal of antibody screening is to help us detect unexpected antibody which may result in transfusion reaction or HDN and also to ensure availability of compatible rbc units for transfusion
I am able to assimilate that we need selectogen to help us identify the antibody. It can be procured commercially or prepared locally. Furthermore, techniques such as LISS and CAT are used. Controls such as weak anti D, c, K, S are required. And in a situation where antibody has been detected, we are urged to go a step further to identify the antibody and its clinical significance. Thank you
Thank you ma for the lecture
In summary,Antibody detection has two stages
Stage1:Antibody screening
Antibody screening test is designed to detect
A.)immune igG antibodies optimally active at 37 degree Celsius
B.)igM antibodies which are active at or near 37 degree Celsius
C.)Should be able to detect autoantibodies active at 37 degree Celsius
Stage2:Antibody identification
Any sample with a positive antibody screen must undergo further investigation to
A.) Identify the antibody
B.)Access the clinical significance
Goal of antibody screening and identification
1.)To detect unexpected antibodies in patients serum/plasma
2.)To identify the antibody/antibodies detected in serum or plasma antibody antibody screening tests
3.)To determine the clinical importance of these antibodies
4.)To ensure the availability of compatible units of blood for transfusion
And antibody screening is specifically done to prevent
1.)Blood transfusion reactions
2.)Help in management,prevention and monitoring of HDN etc.
Unexpected antibodies
Theses are antibodies other than the ABO antibodies that do not occur naturally in the serum of a normal individual.Generally,they occur as a result of red cell stimulation(transfusion or pregnancy).These can be found in 0.3% to 2.8% or the population,depending upon the group of patients or donor study and the sensitivity of the antibody detection method used.
ANTIBODY SCREENING:WHAT IS NEEDED
-Patients details. -
-Date of birth
-Gender/Obstetrics history
-Ethnic origin
-Diagnosis/Clinical condition/Drugs
-Requesting hospital
-Investigation required
-Fully labeled samples
-Screening/panel cells
-SOP/Guidelines
-Antigram(sheet that comes with the commercially prepared screening and panel cells).
Patients serum/plasma tested against
-2 or 3 cell set of screening reagents
-Must be capable of reacting with all clinically significant antibodies in patients sample
-Must be blood group O
-Must be a minimum of 2 individual cells
-Not pooled
-Must give a good antigen expression ie must be homozygous
-Express all antigens whose corresponding antibody is considered clinically significant in TR or HDN.
TECHNIQUES
1.)The patients plasma is tested against the screening cell set of 2 or 3 cells typically
2.)By column agglutination technology (CAT) or tube technique
3.)At low ionic strength (LISS)
4.)At 37oC
5.)Using anti-human globulin(AHG)
6.)At an indirect anti globulin test(IAT)
CONTROLS
Weak anti-D
Weak anti-K
Weak anti-C
Weak anti-Fya
Weak anti-s
A negative reaction is characterized by agglutinated red cell forming a well laminated pellet at the bottom of the micro tube.+1 reaction is characterized by a red cell agglutinate predominantly observed at the lower half of the gel column.There’s also +2,+3,+4 or mixed reaction
RESULTS
1.A negative reaction with each(all)screening cells indicates
-The absence of any clinically significant Ab in the sample tested
2.A positive reaction with any screening cell(or all)indicates
-The presence of an antibody
-At this point we cannot tell if it is clinically significant,Therefore antibody identification is carried out.
Note:
A positive scrub only demonstrates that antibody is present in the sample and doesn’t not show the specificity or indicate the clinical significance,therefore an antibody identification procedure must be carried out.
Unexpected antibodies are antibodies (other than the ABO antibodies) that do not occur normally in the serum of normal individuals.
Generally they occur as a result of red cell stimulation.
Antigram is a sheet that comes with commercially prepared screening cells or panel cell showing the list of antigens present in each vial of the screening cell or panels cells.
Thank you ma,
The lecture was very clear☺️
Please ma, I have a question
what is the difference between screening cells and panel cells?
Nice lecture
Thank you ma for this wonderful lecture. It really inspired me a lot
This has helped me to know that unexpected antibodies do not occur normal in an individual.
It may occur due to stimulation from Red blood cells,, pregnancy and transfusion .
Definition of unexpected antibodies
This are antibodies others then ABO antibodies that don't occur normally in the serum of a normal individuals, this can only be due to Red blood cell, pregnancy and transfusion stimulation.
Reason for detection and identification.
1 During when cross matching is incompatible.
2 when antibodies screening is positive.
Importance of the antibody screening, this help to detect unexpected antibodies so as to prevent transfusion reaction and to help in management and prevention of heamolytic disease of the newborn.
Antibodies identification
Red cells carrying the corresponding antigens must be available.these antigens is in two forms.
1 Screening cells
2 cell panel
This cells should be prepared from group o individuals to prevent reaction, reason group o individuals has no antigens.
Negative results with each screening cells show the absence of any clinically significant antibody in the sample tested.
Positive reaction with any screening cells indicate the present of an antibody, we can't tell if it's clinically significant, further investigation is now reguired to identify the antibody.( Antibodies identification)
Procedure
A patients serum or plasma is tested against the screening reagents.technigue use d is the column agglutination technique or the tube technique.
Control is also reguired, which are weak Anti -D, weak Anti -k, weak Anti - c and weak Anti -s.
Result
Negative --- absence of clinically significant antibody.
Positive --- presence of an antibody.
Thank you ma for the lecture
Well understood
Summary
Antibody screening is a test done to detect unexpected antibody in a patient serum. This is necessary because there are antibodies that do not occur normally in the serum of an individual but occur as a result of red cell stimulation which can be through pregnancy or blood transfusion. When antibody screening is positive it calls for the identification of that antibody, so that blood lacking the corresponding antigen will be selected for transfusion.
For an antibody to be identified,red cells carrying the corresponding antigen must be available, which comes in two forms namely
1. screening cells or selectogen
2. Panel cells
Both of which must be collected from O individuals, so that any positive result will not be attributed to ABO antibodies as O individuals lack A and B antigens.
Antibody screening is carried out to check for unexpected antibodies in serum or plasma,to identify antibody detected in the serum or plasma, to determine the clinical significance of these detected antibodies, to ensure availability of compatible units of red cells for transfusion, to detect immune IgG, IgM antibodies optimally active at 37 degree Celsius, to detect autoimmune problems etc.
Antibody screening is done between patient serum or plasma against 2 or 3 set of selectogen. And these cells must be capable of reacting with clinically significant antibodies in patient samples, must be O individuals, must be a minimum of 2 or 3 individual cells, must not be pooled cells, must have a good antigen expression to be homozygous and must express antigens whose corresponding antibody is considered clinically significant in transfusion reaction or HDN.
Technique
Patient plasma or serum is tested against the screening cells which must be 2 or 3 cells by column agglutination or tube technique at low ionic strength (LISS) at 37 degree Celsius using Anti human globulin (AHG)- at an indirect antiglobulin test and controls such as Weak anti-D,K,c,fya,S etc.
When an antibody screening test is carried out and at the end
A negative reaction with each or all screening cells indicates the absence of any clinically significant antibodies in the tested sample while a positive reaction with any screening cells indicates presence of any antibody which may or may not be clinically significant until a further test is done which is the antibody identification.
Thank u ma and God bless you for this Lecture🙏
I have learnt that Unexpected Antibodies are antibodies (other than the ABO antibodies) that do not occur naturally in the serum of a normal individual. They occur as a result of cell stimulation ( Transfusion or pregnancy).
Antibody screening uses 2 or 3 screening cells to detect if antibodies are present in the serum. If antibodies are detected, they must be identified.
Thank you so much ma for this insightful lecture and congrats on hitting 1k subscribers🥳🥳🥳
On the course of this lecture, I’ve understood clearly that “The antibody screening test” performed in a clinical laboratory is designed to detect the presence of unexpected antibodies, especially alloantibodies in the serum to antigens of the non-ABO blood group system which are considered clinically significant (eg Duffy, Kell, Kidd, MNS, P, and certain Rh types ). And the use of the “antigram” to look for antigens present or absent in each vial of the screening cells or panel cells. And the 3 phase procedures which is used in antibody screening(which are, the Immediate spin, at 37 degree Celsius and AHG)
Good evening ma ,can the child get infected with these antibodies
'Infected' is not the right word to use here. These antibodies that are clinically significant can cross the placenta and destroy red blood cells of the baby causing baby to either die in uterus ie stillbirth, or cause miscarriage or the baby is born with mild or severe jaundice