CONCLUSION & DISCUSSION

Conclusion:

Washing GP’s red cells effectively removed the excess plasma proteins that were causing nonspecific weak agglutination in the initial forward typing, while utilizing the saline replacement technique eliminated the rouleaux formation that was creating pseudo agglutination in the antibody screen.

These results confirmed GP's blood type as group O, RhD positive, resolving the initial discrepancy and establishing his baseline for transfusion support. With his correct blood type now determined, and his antibody screen negative, GP can proceed with his Multiple Myeloma treatment plan knowing that compatible blood products will be readily available if needed during his therapy.

Getting this sorted out is one less thing for GP and SP to worry about as they navigate his new diagnosis and his treatment plan. SP was relieved to have clear answers after all the confusing test results, while GP found some comfort in understanding the logical steps the laboratory took to solve the problem—much like the systematic approach he used to take with his chemistry students. Their anniversary cruise will have to wait, but at least now they know that if GP needs blood products during treatment, everything will be ready. Maybe by next year, he'll be back to his stubborn daily garden routine, and they can finally take that trip.

Discussion:

In patients with Multiple Myeloma, like GP, the disease involves the abnormal proliferation of plasma cells that produce large amounts of a single type of antibody, known as a monoclonal protein or M-protein (paraprotein). This significant increase in plasma proteins can lead to a few common problems in blood bank testing.

The most common issue is rouleaux, where the excess proteins in the patient's plasma alter the surface charge environment around red cells, causing them to stack on top of each other in the test tube and resemble stacks of coins if viewed microscopically. This is not true agglutination, where antibodies bridge red cells together, but it can look like weak agglutination in test tubes or on slides, especially at IS or RT phases of testing. This is why GP's initial ABO/Rh typing and antibody screen showed weak positive reactions that disappeared after troubleshooting.

The saline replacement technique is used to resolve rouleaux when performing tests that use the patient’s plasma. It is performed by removing the patient's protein-rich plasma after centrifugation, without disturbing the cell button, and replacing it with equal amounts of saline. If a true antigen-antibody complex was formed, the red cells will remain agglutinated together. However, if an antigen-antibody complex was not formed and the reactivity was due to rouleaux, the red cells should cleanly disperse in the saline and give a more clearly negative result.

Sometimes those excessive proteins coat the patient's red cells directly and cause false positive reactions in tests utilizing the patient’s red cells due to rouleaux. The saline replacement technique cannot resolve these false positive reactions the same way it can in tests involving the patient’s plasma and reagent red cells. This is because the interfering proteins are attached to the patient’s red cells and not floating in the surrounding plasma like they are in reverse type testing or antibody screen testing.  Thoroughly washing the patient's red cells with saline before performing these tests removes the interfering plasma proteins and allows the typing reagents to interact directly and accurately with the antigens present on the red cell surface, if present, and give good strong reactions, or give cleaner negative results.

So, in GP's case, his Multiple Myeloma led to an excess of plasma proteins, which caused both the rouleaux seen in the initial antibody screen and in his initial forward ABO and Rh typing. The investigative steps of washing the cells and using saline replacement allowed us to 'see through' these protein-related interferences and determine his true blood type and antibody status.