Determination of the number of clotting cells in a sample of blood is known as?

• A. Platelet count
• B. PKU test
• C. Potassium test
• D. PSA

Answer: (A)

Determining the number of clotting cells in a blood sample refers to counting platelets (thrombocytes). Platelets are the small cell fragments that participate in forming a clot and stopping bleeding by creating a plug at injury sites and supporting the coagulation cascade. The test that quantifies them is the platelet count, which is usually part of a complete blood count and reported as platelets per microliter of blood. Normal values are typically about 150,000 to 450,000 per microliter; variations can indicate bleeding risk (low platelets) or a tendency to form clots (high platelets). The other tests mentioned measure entirely different things: phenylketonuria screening, potassium levels, and prostate-specific antigen, none of which assess platelet numbers.