What is the reference range for RBC count in K/uL?

The reference range for red blood cell (RBC) count in thousands per microliter (K/uL) typically varies depending on the specific population and the laboratory standards being used. For adult males, the normal range often falls between 4.7 and 6.1 K/uL, and for adult females, it is usually between 4.2 and 5.4 K/uL. Given this context, the choice that reflects the most commonly accepted range for adults aligns with option B, which presents a range of 4.0-5.7 K/uL.

This range is inclusive enough to accommodate variations due to factors like age, gender, and specific health conditions. The values provided ensure that both males and females fit within normal parameters, capturing the normal physiological variations across different demographics. In clinical practice, having a comprehensive understanding of these reference ranges is essential for interpreting laboratory results accurately and effectively managing patient care.