In a clinical study, an investigator finds a subject with elevated WBC counts but no symptoms. What should be done?

In a clinical study, the presence of elevated white blood cell (WBC) counts may indicate an underlying issue, even if the subject displays no symptoms. Reporting this finding as an unexpected adverse event to the sponsor is essential because it reflects a potential safety concern that could be relevant to the participant's health or the overall integrity of the study.

Unexpected adverse events are defined as any adverse occurrence that is not consistent with the known profile of the drug or intervention being studied, or that has not been anticipated per the study protocol. An elevated WBC count, depending on the context, could suggest a reaction to the treatment or another health issue developing. Reporting it allows for appropriate monitoring and evaluation by the study team and the sponsor, ensuring that the safety of all participants is maintained.

When it comes to the other choices, doing nothing if no symptoms are present disregards the responsibility of the investigator to monitor and report potential safety issues. Reporting it merely as a routine lab variation minimizes the significance of the finding and could lead to critical information being overlooked. Waiting for the WBC count to normalize before reporting may delay the initiation of necessary investigations or safety measures, which could be detrimental to the subject's health. Therefore, timely reporting of unexpected findings, even in the absence