Platelet transfusions are given for thrombocytopenia; a commonly used threshold for transfusion is a platelet count below 20,000 per microliter.

• A. 100,000
• B. 20,000
• C. 50,000
• D. 5,000

Answer: (B)

When platelets drop, the body's ability to stop bleeding diminishes because platelets are the key players in forming the initial plug that seals tiny vessel injuries. A commonly used threshold for prophylactic platelet transfusion is when the count falls below about 20,000 per microliter. At that level, the risk of spontaneous mucosal bleeding and even larger bleeds increases enough that replenishing platelets helps restore hemostasis and protects against new bleeds, especially in patients who are hospitalized, undergoing treatment, or at risk for bleeding.

Higher thresholds are used in situations where bleeding is already present or an invasive procedure is planned—these require more platelets to ensure adequate clot formation. Counts like 50,000 or 100,000 are often cited for such high-risk scenarios, while much lower counts (and in some stable cases, even lower thresholds) may be used for different contexts. Counts significantly above 20,000 would raise the transfusion burden without consistently improving outcomes in the typical prophylactic setting.