Our automated grouping machine didn’t like
a particular sample and so I did a manual blood group. Look at that D rection.
A D-group is positive, or it is not. And if the patient has had a blood
transfusion from a donor of a differing D-group then there are two distinct
populations of D-positive and D-negative cells.
That’s not what is happening here…
My initial reaction was that I’d stuffed
the grouping up somehow and repeated it. And I got the same result…
A partial D
reaction occurs when someone’s red cells have altered Rh(D) proteins (and
therefore antigens) that react with some but not all anti-D typing
reagents. And that looks like what has happened here.
There are many types of
partial D, each with a unique genetic basis. Some people with partial D
have weakly expressed D epitopes and are designated "partial weak D".
Interestingly these references hint that
partial D happens in about 1% of the population… Having a degree in maths (which
I have) and knowing our workload (which I do) I should be seeing
cases like this many times a month.
But I don’t.
Presumably the anti-D we use picks up
the more common variants and only has issues with the more obscure ones?
I am looking forward to see what NHSBT
have to say about this one.
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