WBC counts are reported in which unit?

WBC counts are reported in which unit?

• A. x10^9/L
• B. x10^6/L
• C. x10^3/L
• D. x10^12/L

Answer: (A)

White blood cell counts show how many cells are in a liter of blood. They are on the order of a few billion per liter, so the convenient and standard unit is x10^9/L (roughly 4–11 x 10^9 cells per liter). Using x10^9/L keeps the numbers in a practical range. For comparison, red blood cells are far more numerous, so their counts are reported as x10^12/L. Some labs also report per microliter (µL), which is equivalent for WBCs because 1 L = 1,000,000 µL (so about 4–11 x 10^3/µL).

White blood cell counts show how many cells are in a liter of blood. They are on the order of a few billion per liter, so the convenient and standard unit is x10^9/L (roughly 4–11 x 10^9 cells per liter). Using x10^9/L keeps the numbers in a practical range. For comparison, red blood cells are far more numerous, so their counts are reported as x10^12/L. Some labs also report per microliter (µL), which is equivalent for WBCs because 1 L = 1,000,000 µL (so about 4–11 x 10^3/µL).