Which option correctly lists the normal reference range for adult male hemoglobin (Hgb)?

Which option correctly lists the normal reference range for adult male hemoglobin (Hgb)?

• A. 12.1–15.1 g/dL
• B. 14.5–18.5 g/dL
• C. 11.0–14.0 g/dL
• D. 13.8–17.2 g/dL

Answer: (D)

Hemoglobin levels reflect the blood’s capacity to carry oxygen. For healthy adult men, the normal reference range is about 13.8 to 17.2 g/dL. This range accounts for natural variation among individuals and slight differences in laboratory methods. Values below this range often indicate anemia from causes such as iron deficiency, chronic disease, or blood loss, while values above can suggest polycythemia, dehydration, or factors like living at high altitude or smoking, which can raise red blood cell mass. The ranges listed for other groups or extreme values don’t fit the typical adult male standard, making 13.8–17.2 g/dL the consistent benchmark to expect for a normal male.

Hemoglobin levels reflect the blood’s capacity to carry oxygen. For healthy adult men, the normal reference range is about 13.8 to 17.2 g/dL. This range accounts for natural variation among individuals and slight differences in laboratory methods. Values below this range often indicate anemia from causes such as iron deficiency, chronic disease, or blood loss, while values above can suggest polycythemia, dehydration, or factors like living at high altitude or smoking, which can raise red blood cell mass. The ranges listed for other groups or extreme values don’t fit the typical adult male standard, making 13.8–17.2 g/dL the consistent benchmark to expect for a normal male.