Which set of values represents typical reference ranges for red blood cell, white blood cell, and platelet counts in healthy adults?

• A. RBC 7.0–8.0 million/µL; WBC 1,000–2,000/µL; Platelets 200,000–300,000/µL
• B. RBC 4.5–6.0 million/µL; WBC 4,000–11,000/µL; Platelets 150,000–450,000/µL
• C. RBC 4.0–4.5 million/µL; WBC 20,000–40,000/µL; Platelets 100,000–200,000/µL
• D. RBC 2.0–3.0 million/µL; WBC 30,000–60,000/µL; Platelets 50,000–100,000/µL

Answer: (B)

Understanding normal reference ranges for major blood cell types helps interpret CBC results. In healthy adults, red blood cell counts are typically around 4.5–6.0 million per microliter, white blood cells around 4,000–11,000 per microliter, and platelets about 150,000–450,000 per microliter. The set that matches these norms—RBC 4.5–6.0 million/µL, WBC 4,000–11,000/µL, platelets 150,000–450,000/µL—best reflects the typical values for a healthy individual, indicating normal oxygen transport, immune cell levels, and clotting potential. The other sets include counts that lie outside these normal ranges, suggesting possible anemia, infection/inflammation, or platelet disorders, respectively.