We had a 46 year old male health check patient who has never been transfused before come for blood grouping. He knows his blood group previously as O Rh Positive. Our results were as follows:

	Tube Test	BioRad Gel
-A	1-2+ mf	0
-B	0	0
-AB	2+mf	ND
-D (igG+IgM)	4+	ND
-D (IgM)	4+	4+
A1 Lectin	0	ND
H Lectin	4+	ND
A1 Cells	1-2+ at RT, >2+ at 37 C	w-1+ at RT & 37C
B Cells	4+	4+
O Cells	0	ND
Autocontrol	0	ND
A2 Cells	0	ND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

We repeated the blood group with two other manufacturer’s anti-sera. One anti-sera gave the same result as our tube test result, but with the other anti-sera the result with anti-A was negative.

What should we report the blood group as? O or subgroup of A? Kindly help.

Edited March 29, 20187 yr by aafrin
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I prefer to call it an A subgroup. Maybe some human anti-A can do help, since it is polyclonal, not monoclone as our reagent anti-A.

I also agree with the subgroup of A. However, I would do other tests before considering the case as resolved.
1. Are the reagents you used from different manufacturers from the same clone? Do they have the same title? Differences in clone or titer may lead to differences in reactivity.
2. Tn antigens may be cross-reactive with some anti-A antibodies. Treatment of RBCs with the enzyme may help to exclude this interferant.
3. I would or would refer you to the molecular investigation to identify the deletion mutation at position 261 of exon 6, which characterizes O alleles.
4. Flow cytometry can also assist in the evaluation of the mixed field. Is it happening because of poor reactivity or chimerism?

7 minutes ago, mpmiola said:

3. I would or would refer you to the molecular investigation to identify the deletion mutation at position 261 of exon 6, which characterizes O alleles.

There are MANY more mutation than this leading to O alleles.

Yes, but c.261delG characterizes deleterious O alleles and is not present in alleles A. If this mutation is homozygous, I would suspect a cross-reactivity.

Edited March 30, 20187 yr by mpmiola
missing citation

1 hour ago, mpmiola said:

Yes, but c.261delG characterizes deleterious O alleles and is not present in alleles A. If this mutation is homozygous, I would suspect a cross-reactivity.

Very true.

Reminds me of a donor we had once when I was a reference lab sup.  He had donated 12 times as O NEG.  The next time he donated, they picked up weak typing with Anti-A,B and with further testing, turns out he was a very weak subgroup of A!  Unbelievable.

I agree with A subgroup.  I see a lot of people want to automatically classify the subgroup....but without further testing, that is actually erroneous.  Best to just leave it at subgroup.

Brenda Hutson, MT(ASCP)SBB

On 3/30/2018 at 6:54 PM, mpmiola said:

1. Are the reagents you used from different manufacturers from the same clone? Do they have the same title? Differences in clone or titer may lead to differences in reactivity.

They are from different clones and titer.

We repeated the blood group using BioRad Newborn Card and it showed 2+ with anti-A,B but negative with anti-A.

Definitely an A subgroup.   But clearly with an anti-A1 so best to transfuse group O.  Tube is actually MORE sensitive than gel for ABO