Creatine kinase: race-gender differences in patients hospitalized for suspected myocardial infarction.

Race-gender differences in creatine kinase values were studied in 647 consecutive patients admitted for suspected myocardial infarction. The lowest value in a serial set for each patient was used for group comparisons. Significant differences were found between Hispanic females and black males, using standard values. Using log creatine kinase values, significant differences were found among blacks, Caucasians, and Hispanics. Males had higher log creatine kinase values than females, but no differences were found between sexes within racial groups. Body surface area differences (significant between males and females) did not explain all of the racial-gender differences found. Reexamination of ranges of normality, taking into account race-gender differences, is strongly supported by these data.