Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

Which condition may cause a transient elevation in WBC count results?

1. Altitude change

2. Gender

3. Stress

4. Pregnancy

The correct answer is: Pregnancy

Transient elevation in white blood cell (WBC) count can indeed be attributed to various physiological conditions, with stress being a significant factor known to influence WBC levels acutely. Stress triggers a release of catecholamines and cortisol from the adrenal glands, which can lead to a temporary increase in white blood cells as part of the body's fight or flight response. This elevation is often seen in situations involving both emotional and physical stressors. While pregnancy is associated with an increase in WBC counts due to several factors, including hormonal changes and the physiological adjustment of the immune system to support both the mother and the developing fetus, it is less often described as "transient." Instead, the changes during pregnancy are more sustained, reflecting ongoing physiological adaptations rather than a temporary spike. Altitude changes can also impact WBC counts but typically do so in a more chronic manner as the body acclimatizes to lower oxygen levels rather than as a transient response. Gender, on the other hand, generally does not independently cause variation in WBC count, making it less relevant in this context. Thus, stress is the most recognized condition capable of producing a swift and reversible change in WBC counts, making it the primary focus when considering transient elevations in these laboratory values.