What should be done if serum contains red cells?

When serum contains red cells, re-centrifuging the specimen is the appropriate action to take. The presence of red cells in serum indicates that the sample has not been adequately processed, resulting in incomplete separation of the serum from the cellular components. By re-centrifuging, the red cells can be separated from the serum more effectively, ensuring that the serum is clear and suitable for analysis.

This is especially important in a laboratory setting, where the integrity of the sample can influence test results. If red cells remain in the serum, they can interfere with assays, potentially leading to erroneous conclusions about a patient's health status.

While other options may seem viable, they do not address the core issue. For example, doing nothing would neglect the problem, risking inaccurate test results. Changing to a clean pipette without resolving the presence of red cells would not eliminate the contaminant and might simply transfer the issue. Pouring the serum into a clean tube would not adequately remove the red cells, as they would still be present unless a proper centrifugation is performed. Therefore, re-centrifuging is the correct and effective approach to achieve a clear serum sample.