University of Tabuk Faculty of Applied Medical Sciences Department Of Medical Lab. Technology 4 th Year – Level 8 – AY 1435-1436

University of Tabuk

Faculty of Applied Medical Sciences

Department Of Medical Lab. Department Of Medical Lab. TechnologyTechnology

4th Year – Level 8 – AY 1435-1436

The Blood Typing(Blood Grouping)

By : Mr. Waggas Elaas

BB CR 2014-2015 Mr.Waggas 2


• Review• ABO direct & Indirect grouping• Subgroups of A• Gel cards• ABO grouping discrepancies • Rh grouping• Du and weak D methods• Automated methods

Topic Outlines

•The differences in human blood are due to the presence or absence of antigens and antibodies.

•The antigens are located on the surface of the RBCs and the antibodies are in the plasma.

•Individuals have different types and combinations of these molecules.

•The blood group you belong to depends on what you have inherited from your parents.

What are the different blood groups?


• There are more than 20 genetically determined blood group systems known today

• The AB0 and Rhesus (Rh) systems are the most important ones used for blood transfusions.

• What are the other blood groups??

What are the different blood groups?


Blood Types

http://www.bloodbook.com/world-abo.html


• The "A“ and "B" antigens are also produced by some other plants and microorganisms. Thus, individuals who do not recognize one or more of these antigens as "self" will produce antibodies against the plant or microbial antigens.

• These antibodies will also react with human antigens of the same kind whether introduced via a blood transfusion or a tissue graft.

Why do individuals produce antibodies to antigens they do not have?


Parent

Allele

ABO

A??????

B??????

O??????

Possible Blood group Genotypes


Parent

Allele

ABO

AAAABAO

BABBBBO

OAOBOOO

Possible Blood group Genotypes


The ABO blood groups

• The most important in assuring a safe blood transfusion.

• The table shows the four ABO phenotypes ("blood groups") present in the human population and the genotypes that give rise to them.

Blood Group

Antigens on RBCs

Antibodies in Serum Genotypes

A A Anti-B AA or AO

B B Anti-A BB or BO

AB A and B Neither AB

O Neither Anti-A and anti-B OO 10


ABO & RH are the Most important (clinically significant) Blood Group Systems for transfusion practice.

Why??


Bombay blood group:

The Bombay blood group lacks H gene and therefore cannot make H antigen (H substance). Since the H substance is the precursor for the A and B antigens, these antigens also are not made. The cells type as O and the serum has anti-A, anti-B, and anti-H since the individual lacks all of these antigens. Anti-H agglutinates O cells. The only cells Bombay individuals do not agglutinate are from other Bombay blood people since they lack the H antigen

ABO Subgroups


The subgroups of A and B are caused by decreased amounts of antigen on the red blood cells. They are inherited conditions.

The A blood group contains about twenty subgroups, of which A1 and A2 are the most common (over 99%). A1 makes up about 80% of all A-type blood, with A2 making up almost all of the rest.

There are other, weaker subgroups of A exist: A3; Aint; Am, Ax; Ael. Each has a different pattern of reacting with anti-A, anti-A, and various antibody-like substances called lectins.

Lectins are extracts of seeds of plants that react specifically with certain antigens. The two most common lectins used in Blood Bank are:Ulex europaeus, or lectin H, which agglutinates cells that have H substance.Dolichos biflouros, or lectin A1, which agglutinates cells with A1, but not A2

Difference Between A1 and A2

• A1 has more A and less H antigen on the cell.

• A2 has less A and more H antigen

• A2 can produce anti- A1 – qualitative difference.

More complicated blood group system.Contains about 50 antigens.The most clinically important ones are : C,c,E,e and D.(D) Is the most important and most immunogenic.The person is said to be Rh positive if he had the D antigen, and Rh negative if he hadn’t.

So, for example, some people in group A will have it, and will therefore be classed as A+ (or A positive).

While the ones that don't, are A- (or A negative).

And so it goes for groups B, AB and O.

The Rhesus (Rh) System


• Rh antigens are transmembrane proteins with loops exposed at the surface of red blood cells.

• They appear to be used for the transport of carbon dioxide and/or ammonia across the plasma membrane.

• They are named for the rhesus monkey in which they were first discovered.

• RBCs that are "Rh positive" express the antigen designated D.

• 85% of the population is RhD positive, the other 15% of the population is running around with RhD negative blood.

The Rhesus (Rh) System (Cont.)


Rh Blood Group and Rh Incompatibility

A person with Rh- blood does not have Rh antibodies naturally in the blood plasma.

Rh system is the commonest in causing HDN (HDFN) = Hemolytic Disease of Fetus and Newborn.

This occurs due to mother – fetus Rh incompatibility : D negative Mother having a D positive Fetus.



Laboratory Methods

For ABO :1. Direct (forward) Slide/ Tube method. (also called cell grouping).Detects what???2. Indirect (reverse) tube method. (also called serum grouping).Detects what??3. Gel cards for ABO/Rh grouping

For Rh :1. Direct Slide/ Tube method. Detects what??2. Du method .Detects what??


Anti-seraColorSource

Anti-ABlueGroup B donor

Anti-BYellowGroup A donor

Anti-A,B (Optional)Colorless (clear)Group O donor


Describe the direct and indirect slide and tube method for ABO & Rh grouping.

Describe the Du method for weak D .


• Illustration of the forward and reverse grouping reaction patterns of the ABO groups using a blood group tile

22


Gel Cards – How to read?

Look at the photo above. Reactions are graded from 0 to 4+. Reading from left to right: 4+ reaction is indicated by a solid band of red cells on the top of the gel; 3+ reaction displays agglutinated red cells in the upper half of the gel column; 2+ reaction is characterized by red cell agglutinates through the length of the column; 1+ reaction is indicated by red cell agglutinates mainly in the lower half of the gel column with some unagglutinated red cells pelleted at the bottom; and Negative reactions display a pellet at the bottom and no agglutinates in the matrix of the gel column. A mixed field reaction may be observed.


First ABO/D type:1. Anti-A 02. Anti-B 4+3. Anti-D 4+ Second ABO/D type:1. Anti-A 4+2. Anti-B 3+3. Anti-D 0


Now guess!

People with blood group O are called "universal donors" and people with blood group AB are called "universal receivers."

Are these terms are 100% accurate? Why?

Blood transfusions – who can receive blood fromwhom?


Blood Group

Antigens Antibodies Can give blood to

Can receive

blood from

AB

A

B

O


Blood Group

Antigens Antibodies Can give blood to

Can receive

blood from

AB A and B None AB AB, A, B, O

A A B A and AB A and O

B B A B and AB B and O

O None A and B AB, A, B, O O


ABO Discrepancies

• Discrepancy between forward and reverse• Helpful observations

– Strength of reaction: forward 4+ if antigen present, reverse 2-4+.

– Unexpected negative in reverse– Unexpected positive in forward OR reverse

• Must delay transfusion until resolved – emergency give out O RBCs and appropriate D type

ABO Discrepancies

• Errors divided into two categories– Technical– Sample

• Results in false positives and negatives

• Sample errors divided into RBCs and serum

ABO Discrepancy – Technical False Negative

• Failure to add serum or antiserum to a test.• Failure to identify hemolysis as a positive reaction.• Not using the appropriate serum (or reagent) to cell ratio.• Improper centrifugation.• Incubation of tests at temperatures above 20-25 C.• Use of inactive reagents.• Failure to interpret or record test results correctly.

ABO Discrepancy – Technical False Positive

• Over centrifugation

• Use of contaminated reagent antibodies, RBCs or saline

• Use of dirty glassware

• Incorrect interpretation or recording of results

• Weak subgroups of A or B.• A, B or AB individual transfused with massive quantities of group O blood.• ABO non-identical bone marrow or stem cell transplant.• Inhibitor substances which neutralize anti-A or anti-B. • heavy protein coating of the red blood cells. • coating of cord blood cells with Wharton's jelly.• antibodies to dyes used to color anti-A or anti-B• Patient is an infant.• Patient is elderly.• Seriously immunocompromised due to disease, therapy or depressed immunoglobulin

levels.• Large amounts of IV fluids present due to treatment or drawing blood above an IV.• Antibodies passively transfused in non-ABO identical products containing excessive

plasma, usually platelets.

• Anti-A1 is not uncommon in A2 or A2B individuals.

33

ABO Discrepancy – sample errors

Automation in Blood Grouping

• A highly sensitive image analysis reader for the interpretation of blood grouping plates, gel cards and other agglutination based assays

• Suitable for ABO/Rh grouping, antibody screening etc

• Reads all varieties of plates and gel type cards


The Qasar IV

• a high-capacity, semi-automated blood grouping system designed to process batches of up to 96 samples at a time. It is suitable for the larger hospital blood bank and donor centres, performing:

ABO Grouping Rh Typing Antibody screening Cross matching



WADiana Compact is a fully automated immuno-haematology analyser, which can perform steps such as positive identification of samples and reagents, red cell suspension and dilution and pipetting of sample and reagents through integrated and continuous process. It is easy to use with maximum security including clot detection and ensuring no contamination.- World 1st fully automated analyzer for gel cards- Real "Gel" Agglutination Technique (GAT)- FDA 510K Certification, CE Marked, ISO9001, SFDA etc.- Over 3000 installations worldwide- Unique 8-column Gel card- Easy & user-friendly Interface


The ORTHO AUTOVUE System is the premier fully walkaway, random access instrument for blood typing and compatibility testing.

MLT408 BB-CR, Mr. Waggas 38

Documents

University of Tabuk Faculty of Applied Medical Sciences Department Of Medical Lab. Technology 4 th Year – Level 8 – AY 1435-1436