I'm getting back into the
swing of crossmatching. I did it for years; and the old skills are
returning. Following the detection of a positive result in an
antibody screen this morning in the plasma of a patient requiring a
blood transfusion, an antibody identification panel was performed by
both indirect antiglobulin and enzyme techniques.
The results: positivity
in screening cells two and three and in panel cells two, three, five
and six. All other cells clearly negative.
The conclusion:
frustration. This pattern corresponds to nothing.
However...
The indirect antiglobulin
panel is stronger in cells two and six; and weaker in cells three and
five. The enzyme panel is the converse of this - stronger in cells
three and five and weaker in cells two and six.
Positivity in only cells
two and six would be consistent with anti-K
Positivity in cells three
and five would be consistent with anti-E
Therefore we have two
blood group antibodies present; anti-K working stronger by indirect
antiglobulin and anti-E working stronger by enzyme, but both
antibodies detectable by both techniques. As one would expect from
such antibodies.
Reviewing the screening
cells shows that such a combination of antibodies is consistent with
these findings. Furthermore the patient tests negative for these
antigens.
In this instance
provision of suitable blood for transfusion is straightforward; donor
units come pre-typed for these antigens. No mass screening (and
hoping for) suitable donor blood is necessary.
All that is required is a
crossmatch... I can do that...
Fortunately for my sanity
the reference laboratory sends detailed instructions on how to
consider the patient and on what blood products they should be given.
