15 May 2014 (Thursday) - Crossmatching Problems
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.
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...
Labels: case study