How does the laboratory determine which direction the investigation should take?

How does the laboratory determine which direction the investigation should take?

Each laboratory has standard operating procedures that define the extent of the preliminary laboratory investiga-tion. The first step in any investigation is a clerical check. This check involves comparing identifying information on the transfusion request, blood product label, compatibility label, pre- and post-transfusion blood samples, and blood bank product release record. The purpose of the clerical check is to determine whether the product implicated in the investigation was transfused to the individual for whom it was intended.

The next step is a hemolysis check. The color of plasma/serum from pre- and post-transfusion samples is compared for hemolysis and direct antiglobulin testing is performed on the pre- and post-transfusion samples.

The ABO and Rh type are also repeated on the pre- and post-transfusion samples when the product implicated in the reaction is a red cell product. This testing is not rou-tinely performed for non-red-cell products, such as plasma or platelets, unless there is evidence of red cell destruction. If there is evidence of a hemolytic reaction, the type and screen and compatibility tests are completed on the pre- and post-transfusion samples.

In summary, the preliminary laboratory investigation determines whether the implicated product was transfused to the appropriate patient and classifies the reaction as hemolytic or non-hemolytic. Additional testing is based on the patient’s signs and symptoms, the differential diagnosis that this information suggests, and the specific product involved in the investigation.