Which value is expressed as a percentage in reference ranges?

Which value is expressed as a percentage in reference ranges?

• A. Hematocrit
• B. WBC count
• C. Platelet count
• D. Hemoglobin

Answer: (A)

Hematocrit is expressed as a percentage because it represents the proportion of blood volume made up by red blood cells. It’s a ratio: (volume of red cells ÷ total blood volume) × 100, so the result is a percent. The other values are given as counts or concentrations: white blood cells and platelets are reported as numbers per microliter (or per liter in SI units), and hemoglobin is reported in grams per deciliter. For example, normal ranges hover around hematocrit roughly 40–54% in men and 36–46% in women (lab-specific ranges can vary). WBC counts are typically about 4.0–11.0 x10^9/L, platelets about 150–450 x10^9/L, and hemoglobin about 13.5–17.5 g/dL in men and 12.0–15.5 g/dL in women.

Hematocrit is expressed as a percentage because it represents the proportion of blood volume made up by red blood cells. It’s a ratio: (volume of red cells ÷ total blood volume) × 100, so the result is a percent. The other values are given as counts or concentrations: white blood cells and platelets are reported as numbers per microliter (or per liter in SI units), and hemoglobin is reported in grams per deciliter. For example, normal ranges hover around hematocrit roughly 40–54% in men and 36–46% in women (lab-specific ranges can vary). WBC counts are typically about 4.0–11.0 x10^9/L, platelets about 150–450 x10^9/L, and hemoglobin about 13.5–17.5 g/dL in men and 12.0–15.5 g/dL in women.