what is abo discrepancy

Full Answer

What are the causes of ABO discrepancy?

ABO discrepancies may be due to clerical errors or technical problems with a sample or during testing. Intrinsic problems within red cells or plasma may also lead to ABO discrepancies. Although many advances have been presented for ABO blood grouping, discrepancies still occur.

What are the categories of discrepancies in the ABO typing?

Classifying ABO DiscrepanciesCold or room temperature reactive allo- or autoantibody reacting with antigens on the reverse grouping cells.Excess serum protein resulting in rouleaux formation.Passively transfused antibody in the transfusion of plasma components or the administration of IVIG.More items...

How do you deal with ABO discrepancies?

Group 1 DiscrepanciesAdd one or two extra drops of plasma to the reaction.Incubate at room temperature for 15-30 minutes.Incubate at 4°C for 15 minutes.

What is the first step in resolving an ABO discrepancy?

Although not mentioned for each discrepancy discussed, the first step in resolving a discrepancy would be to repeat the ABO group using a fresh aliquot of washed red cells. Reactions that were unexpectedly weak or negative would be read microscopically.

What happens when an ABO blood type is mismatched?

Transfusion with ABO incompatible blood can lead to severe and potentially fatal transfusion reactions. RhD is highly immunogenic and can lead to red cell haemolysis in certain settings.

Why is it necessary to resolve ABO discrepancies?

ABO discrepancies describe scenarios that result in unexpected reactions in the ABO forward and reverse typing reactions. This makes the determination of the patient's blood group uncertain and can pose a threat to the patient's safety by transfusion of incompatible blood products.

Does ABO incompatibility go away?

Blood incompatibility between a mother and baby can cause various complications, including anemia and jaundice. For ABO incompatibility, the effects are usually mild and go away with time, but with Rh incompatibility, the consequences can be very serious.

Can ABO incompatibility be treated?

How is ABO incompatibility treated? ABO incompatibility is treated in newborns by light therapy (phototherapy). On rare occasions an exchange transfusion may be necessary. Full recovery usually occurs with no lasting repercussions.

What are the symptoms of ABO incompatibility?

The following are symptoms of ABO incompatible transfusion reactions:Low back pain.Blood in urine.Chills.Feeling of "impending doom"Fever.Nausea and vomiting.Shortness of breath.Increased heart rate.More items...•

How do you spot a discrepancy?

How do you identify discrepancies in data? Identifying discrepancies in data is simple. You compare two data sets for the same period of time and look for numbers that don't match up. The real challenge is understanding what caused the discrepancies and how to reconcile them.

What are the complications of ABO incompatibility?

ABO-incompatible blood transfusion often causes acute hemolytic reaction followed by disseminated intravascular coagulation (DIC) and acute kidney injury (AKI).

Which commonly leads to ABO incompatibility errors?

Subsequent human and process errors can occur around the two main events – specimen collection from recipient and administration of blood. The two most common reasons for HTRs due to incompatibility are: Mislabeling of the recipient blood on initial collection. Transfusing blood to the wrong patient.

What are the 4 types of blood in the ABO blood typing system?

The ABO system blood group A – has A antigens on the red blood cells with anti-B antibodies in the plasma. blood group B – has B antigens with anti-A antibodies in the plasma. blood group O – has no antigens, but both anti-A and anti-B antibodies in the plasma. blood group AB – has both A and B antigens, but no ...

What are the 4 possible phenotypes in the ABO classification system?

The four basic ABO phenotypes are O, A, B, and AB.

What are rare Group II discrepancies?

Group I - Discrepancies that are associated with unexpected reactions in the reverse grouping. Group II - Discrepancies that are associated with unexpected reactions in the forward grouping. Group III - Discrepancies between forward and reverse grouping caused by protein or plasma abnormalities.

Which commonly leads to ABO incompatibility errors?

Human error is the most likely cause of an ABO incompatibility reaction. If your transfusion uses the wrong blood type, it could be the result of mislabeled blood, incorrectly completed forms, or a failure to check donated blood before the transfusion.

What temperature can cause agglutination?

Incubation at 4°C requires the use of auto-controls or control O+ cells as incubation at cold temperatures can cause agglutination due to activation of commonly-occurring cold-agglutinins such as anti-I, which react with all adult RBCs

How long to incubate a rbc at room temperature?

Incubate at room temperature for 15-30 minutes. Incubate at 4°C for 15 minutes. Incubation at 4°C requires the use of auto-controls or control O+ cells as incubation at cold temperatures can cause agglutination due to activation of commonly-occurring cold-agglutinins such as anti-I, which react with all adult RBCs.

How to treat BGSS?

For patients with BGSS: Wash red cells and suspend them in saline instead of plasma. For patients with low-incidence antigens which may react with antibodies in the antisera: Change lot numbers; the new lot should not have the low-incidence antibody and thus will not non-specifically react with the red cells.

What is the presence of other allo-antibodies to high-incidence antigens reacting with?

Presence of other allo-antibodies to high-incidence antigens reacting with reagent cells

What is the B phenotype of E. coli?

Polysaccharide of the E. coli O86 subtype (often associated with colorectal cancer) Can cause an “acquired B” phenotype in group A individuals due to adsorption of a B-like polysaccharide from E. coli. B-line polysaccharide reacts with human source anti-B.

Can BGSS neutralize antisera?

BGSS in patient’s serum can neutral ise antisera used in forward grouping

Which disease can weaken antibody expression?

Antigen expression often follows disease course (gets stronger if disease enters remission) Diseases which can weaken antibody expression: CLL or myeloma which can be associated with hypogammaglobulinaemia. Resolve by running protein electrophoresis or demonstrating low IgG, IgA and IgM.

How to listen to ABO discrepancies?

For that reason, the best way to listen to this episode is with the cases printed out or viewed on your computer, tablet, or mobile device screen. You can find everything you need to visualize what Dr. Draper describes in the interview further down on this page. My advice: Print out the handout and have it in front of you so you can try to solve the cases along with Dr. Draper.

Is ABO testing the same as reverse grouping?

When ABO testing goes right, as it almost always does, it’s a very simple process. The forward grouping agrees with the reverse grouping (or the “front-type” is the same as the “back-type,” to use blood bankers’ lingo), and there is no question about what type of blood to give to a patient.

What are the different methods of ABO testing?

These vary from slide testing to tube testing and microplate testing.

Why is it important to diagnose multiple myeloma?

The patient’s diagnosis is very important in resolving discrepancies as patients with malignancies are often treated with chemotherapy that causes im-munosuppression, giving antibodies a weak appearance. Patients who are diagnosed with multiple myeloma will usually have large amounts of proteins present, and these will cause rouleaux formation or abnormal aggregation of the red cells, which can mask true agglutination. To correct this problem, cell suspensions must be carefully washed, and the serum sample should be diluted with saline to the point where rouleaux is no longer present. 2

What blood group is used for back typing?

Within the “A” blood group are several subgroups which may at times react with the A1 used in back typing, resulting in a discrepancy. Most of the time it will be an A2 or an A2B individual. Typing the cells with anti-A1 lectin ( Dolichos biflorus) will help resolve this problem.

What is the phenotype of Bombay?

A phenotype that is rarely encountered is the Bombay or Oh phenotype. The cells of a Bombay individual will forward and back type as a group O, because they lack the antigens A, B and H , and have anti-A, anti-B and anti-H antibodies. While a discrepancy does not appear at first, the problem surfaces when the patient’s serum is tested against O cells. Since anti-H is present they will agglutinate these cells.

What happens when Tn activated cells are encountered?

Acquired A occurs when Tn activated cells are encountered because of a somatic mutation which results in some hematopoietic cells incapable of synthesizing certain oligosaccharide side chains entering the circulation in the Tn polyagglutinable state. The Tn and A cells have the end sugar N-acetyl-galactosamine and will be agglutinated by the anti-A antisera. The use of proteolytic enzymes in this situation would be beneficial as this would degrade the acquired A antigen. 5

What is acquired B?

Another serological problem occasionally encountered involves the acquired B and acquired A antigens. The acquired B problem is encountered when bacterial enzymes deacetylate the A1 antigen, causing it to react weakly when tested with anti-B antisera. Usually associated with patients diagnosed with carcinoma, this problem is not commonly seen as most blood banks use monoclonal reagents, and acquired B may or may not react with a monoclonal anti-B.

Can cold autoantibodies be used for back typing?

In this situation, pre-warming of all reagents and blood samples used will resolve the problem. There are other antibo dies that react at room temperature, which may bind with the cells used for back typing if these cells contain the corresponding antigen. These include antibodies to the M and P1. Once all other factors have been ruled out it may be necessary to resolve the discrepancy by testing with various lot numbers of back typing cells to see if different reactions are obtained, and testing screening cells or even a panel of cells at room temperature to arrive at an antibody specificity.

Objectives

Demonstrate knowledge and understanding of ABO testing and result interpretation.

Additional Information

Intended Audience: Medical laboratory scientists, medical technologists, and technicians. This course is also appropriate for medical laboratory science students and pathology residents.

What is acquired B antigen?

Acquired B antigen. a. Patients with acquired B antigen will have results typical of a patient with A type blood but will also have a 1+ or 2+ reaction in the forward typing with anti-B. This can be caused by a type of gastrointestinal disease where bacteria change the A antigen sugar to appear like B antigen.

Why is blood banking important?

An important part of blood banking is knowing how to deal with unexpected results. Discrepancies in the blood bank are common and knowing how to solve them is critical. They can be caused by patient RBCs, patient serum, an underlying condition, human error, or a number of factors. Blood cannot be released if there is an unresolved discrepancy.

Can blood be released if there is an unresolved discrepancy?

Blood cannot be released if there is an unresolved discrepancy. Here are a few common discrepancies to be aware of. 1. Patient has A2 RBCs and anti-A1. a. Remember not all people with A2 blood make anti-A1, in fact most don’t.

What is acquired B?

Acquired B Phenomenon – an uncommon ABO discrepancy that occurs only in group A patients with diseases of the digestive tract. Enzymes produced by some gram-negative bacteria remove a part of the A antigen (specifically, the acetyl group from the last sugar on a group A chain, N-acetylgalactosamine), leaving behind a modified sugar, galactosamine, that makes the chain resemble the B antigen--the B antigen-specific sugar is galactose. This “faux” B antigen cross-reacts with fresh human anti-B as well as monoclonal anti-B testing reagents.

What is an ABO discrepancy?

ABO discrepancy is a generic term for a variety of situations in which the interpretation of a patient or donor ABO grouping results is unclear. These discrepancies occur when unexpected negative or positive reactions occur in the forward or reverse grouping. ABO discrepancies happen for a wide variety of reasons, including technical errors, problems with red cell antigen (forward grouping), problems with serum antibodies (reverse grouping), or problems with serum and cells.

What is a CG?

CG is a 100-year-old woman who fell and broke her hip. She has been admitted to the hospital and a type and screen is ordered. The antibody screen is negative. ABO/Rh typing was requested.

What is AD in ER?

AD is an 86-year-old man brought to the ER from an assisted living facility. He was diagnosed with acute anemia of unknown origin when his CBC revealed a hemoglobin of 4.0 gm/dL with a hematocrit of 12%. A STAT type and screen for two units of blood was ordered. The patient was typed as Group B Rh Positive and his antibody screen was negative. Two units of Group B Rh Positive blood were found to be crossmatch compatible and one unit was released for immediate transfusion. Shortly after the transfusion began, the patient reported severe chest and back pain and shortness of breath. He became tachycardic and his blood pressure dropped significantly. The transfusion was stopped and samples were collected for a transfusion reaction workup. A type and screen on the post-transfusion samples was ordered.

Mixed Field Reactions

See more on learnhaem.com

Technical Errors

Abo Antigens in Disease States

Group 1 Discrepancies

Group 2 Discrepancies