Which values define normal laboratory reference ranges for a newborn CBC?

• A. RBCs 4-6 x10^6/µL; Hb 12-16 g/dL; Hct 40-50%; WBC 4,000-11,000/µL
• B. RBCs 2-3 x10^6/µL; Hb 8-10 g/dL; Hct 25-35%; WBC 15-25k/µL
• C. RBCs 6-8 x10^6/µL; Hb 14-18 g/dL; Hct 50-60%; WBC 5-15k/µL
• D. RBCs 3-5 x10^6/µL; Hb 10-14 g/dL; Hct 30-40%; WBC 3-9k/µL

Answer: (A)

Normal newborn CBC reference values describe a healthy balance across the four components without showing anemia, polycythemia, or abnormal white cell counts. In healthy term newborns, the red blood cell count is typically in the mid 4 to 6 million per microliter range, hemoglobin around the low to mid teens, hematocrit roughly in the 40–50% range, and white blood cell count commonly between about 4,000 and 11,000 per microliter. This combination fits what’s expected for a normal newborn: not too low in Hb/Hct, not drastically high, and with a WBC range that’s within the common neonatal baseline. The other sets would imply anemia (low Hb/Hct), polycythemia (high Hb/Hct), or abnormal WBC levels that aren’t characteristic of a normal newborn, making the chosen option the best match.