Samples from the same patient show a change in results on two consecutive days. How should the request for crossmatch be handled?

In situations where samples from the same patient show differing results on consecutive days, collecting a new sample and repeating the tests is the most prudent course of action. This approach allows for the validation of results, ensuring that any inconsistencies are thoroughly evaluated before proceeding with a crossmatch.

The primary concern is the reliability of the test results; if there is a significant difference between the two samples, it raises questions about either the test methodology or the patient's condition at the time of testing. Factors such as changes in the patient's immunologic state, possible transfusion reactions, or assay variability could lead to discrepancies. By obtaining a new sample, the laboratory can confirm the patient's current serological status and secure an accurate crossmatch.

Using either of the initial samples for a crossmatch without reassessing them could lead to incorrect transfusion decisions, putting the patient at risk. Therefore, opting to collect a new sample is essential for ensuring the safety and appropriateness of the transfusion process.