CK reference range for males?

• A. CK 30-135
• B. CK 55-170
• C. CK 80-200
• D. CK 15-90

Answer: (B)

Creatine kinase is an enzyme found mainly in muscle, and normal values depend on sex because men typically have more muscle mass. That means adult males tend to have a higher reference range than females, and laboratories set ranges based on the assay they use.

Among common lab references, the range that sits in the middle of the options best reflects what many clinical labs report for adult males. It accounts for the typical baseline level without being as low as ranges that may be seen in other groups or as high as ranges that exceed what’s commonly accepted for healthy adult males. Keep in mind that exact numbers can vary by the specific test method and the lab, so always check the lab’s stated reference range on a report.

So, the middle option is the best match because it aligns with the sex-specific adjustment for males and with the range many labs use as the normal reference.