After a transfusion reaction, which test should be performed on the patient’s sample?

Following a transfusion reaction, the direct antiglobulin test is the most appropriate test to perform on the patient’s sample. This test is designed to detect antibodies that are bound to the red blood cells. In the context of a transfusion reaction, it helps determine whether the patient's immune system has responded to the transfused blood by forming antibodies against the donor red blood cells.

When a transfusion reaction occurs, it is critical to identify whether there has been any hemolysis of the transfused red blood cells, which can be evidenced by the presence of IgG antibodies on their surface. The direct antiglobulin test detects these antibodies, which can indicate a hemolytic reaction. This test is crucial for diagnosing conditions such as acute hemolytic transfusion reactions and identifying incompatible blood types.

While other tests can provide useful information, they do not specifically address the immediate clinical concern after a transfusion reaction. For instance, the indirect antiglobulin test is generally performed to screen for irregular antibodies before transfusion, rather than to assess reactions post-transfusion. ABO typing and Rh typing help confirm blood type compatibility before transfusion and are not primarily diagnostic for reactions. Hence, the direct antiglobulin test stands out as the key procedure in the post