American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

What does a high white blood cell count typically indicate?

1. Anemia

2. Infection

3. Dehydration

4. Thrombosis

The correct answer is: Infection

A high white blood cell count typically indicates the body is responding to an infection. White blood cells, or leukocytes, play a crucial role in the immune system, identifying and combating pathogens like bacteria, viruses, and other foreign invaders. When an infection is present, the body increases the production of white blood cells to help fight off these pathogens, leading to an elevated count in the bloodstream. This immune response is a vital part of maintaining health and responding to illness. While other factors can cause fluctuations in white blood cell counts, such as dehydration, which can concentrate the blood and give a misleading count, or anemia and thrombosis, which are not directly related to white blood cell production, the most common physiological cause of a high WBC count is indeed an infection. Hence, identifying a high count usually prompts further investigation to determine the underlying cause, with a particular focus on potential infections.