3.4 Blood Grouping, as easy as A, B NICE€¦ · Blood Grouping: As Easy as A,B..??? • Testing...

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Blood Grouping: As Easy as A,B…???A Case of an Unusual B GroupKelli Quantock, Mater Health , Brisbane


Blood Grouping: As Easy as A,B..???

Case Report• A 34 year old female first presented to Mater Pathology with a request for a

group and hold serum pre‐operatively for a gynaecological procedure in 2014• Blood Group performed on the Ortho Innova using the ABD Rev Card and CSL

Revercells. • Results are • Anti‐A – 1+• Anti‐B – 4+• Anti‐D – 4• Control – Negative• A1 cells – 3+• B cells ‐ Negative

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• The Mater uses Ortho BioVue ABD Reverse cards and CSL 0.8% Abtect cells.

• The following results were obtained using immediate spin of the BioVue card for 5 min.

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???? So is it a

• Group B,

• a Subgroup AB or

• an acquired B.

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Or are we trying to push a square peg into a round hole??

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• Testing with anti‐A1 lectin was negative.

• The blood group was initially reported as an AB with an anti‐A1, possibly an AsubgroupB.

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Blood Service Results

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• Group B Positive (most probable genotype R1R2)

• Phenotype D+C+E+c+e+K‐

• DAT negative



The Results from the Research and Development Lab

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• 8 genetic variations related to the sample request reported:

• 6 mutations defining the ABO*BA.03 allele and the B(A) phenotype.

• 2 mutations defining ABO*O1.26 allele and the O phenotype.



When considered together the genotype is therefore:

ABO*BA.03/*O.01.26 with a predicted ABO phenotype of

B(A)This means the patient predominantly has B antigen on her red cells, with a minuscule bit of A antigen too.

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• The B(A) phenotype was first described in 1985 after a murine anti‐A BioClone (Ortho Clinical Diagnostics) monoclonal antibody was released.

• It was found this new monoclonal anti‐A was reacting with red cells previously typed as Group B.

• At the time, this was interpreted that a small amount of A antigens were being produced on the red cells either as an expression of elevated B transferase, or an an overactive example of the enzyme and was termed B(A).

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• The B(A) phenotype is autosomal dominant, and as the Chinese study in 2007 by their Blood Service found, runs in families.

• To date, 5 alleles have been described B(A)01, B(A)02, B(A)03, B(A)04 and B(A)05 by nucleotide sequencing.

• Our patient has one copy of the B(A)03 allele.

• The incidence of this allele is rare.

• There are also instances of the A(B), where small amounts of B antigens are found in A cells.

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• In B(A) individuals, the α1,3 galactosyltransferase enzyme catalyzes the transfer of sufficient N‐acetylgalactosamine(GalNAC) to its acceptor substrate to permit agglutination by certain anti‐A antisera.

• In these individuals the GTB (glycosyl transferase for B) can be up to 5‐6 times more active than that of most other Group B individuals.

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Laboratory Differentiation

• AABB Technical Manual 18th edition described people with this group have plasma which reacts with both A1 and A2 cells.

• The B(A) cells can show varying reactivity with monoclonal anti‐A results however most cases are detectable with monoclonal typing reagents which contain the MH04 clone.

• In general, the agglutination is weak, with fragile easily dispersed aggregates.

• This correlates with our laboratory findings.

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• Testing with polyclonal anti‐A antisera or a different anti‐A monoclonals should lead to a potential identification.

• Adsorption and elution techniques can be used to test for possible weak subgroups of A and exclusion.

• A substance is not detected in secretors.

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• Clinical Significance

• It is important to identify the correct blood group as there can be impacts if this patient is classified as a Group AB and the clinical significance of the anti‐A1 is not tested at 37oC.

• Potentially, this patient may receive group AB red cells with hemolytic consequences.

• It is important that all cases of blood group discrepancies are investigated and Group O blood given until discrepancies are accounted for.

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THANK YOU

Blood Service, Red Cell Reference Lab and Glenda Millard and Catherine Hyland from the Research and Development Department

and to Arthur Joyce

Nevertheless.. He persisted.

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• She represented in 2017, the serological results were similar to previous.

• Again the presence of the positive reaction in the Ortho A well was confirmed.

• The cells were tested by tube with CSL monoclonal anti‐A, the reactions were too weak and broke up easily.

• Not able to be described as reliably positive.

• So the sample was sent to the Blood Service for further Blood Grouping studies.

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• The Mater Blood Bank then re‐examined our results.

• The reactions in the Ortho A well were re‐confirmed by automated techniques and the Blood Service were queried as to other possibilties.

• The sample was then referred to the Blood Service Research and Development Department for Targeting DNA Sequencing

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3.4 Blood Grouping, as easy as A, B NICE€¦ · Blood Grouping: As Easy as A,B..??? • Testing...

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