[Critical evaluation of changes of serum CK after exertion in the identification of carriers of Duchenne's muscular dystrophy].

Serum creatine kinase activity is the most useful test for Duchenne muscular dystrophy carrier detection, but only in 50-80% the carriers do have increased serum creatine kinase activity. To evaluate the diagnostic accuracy of post-exercise serum creatine kinase activity in identifying Duchenne muscular dystrophy carriers we did determine it in normal and possible Duchenne muscular distrophy carrier women. Creatine kinase activity was determined in basal conditions and at predetermined time intervals up to 10 hours after a constant exercise on a cycloergometer. Statistical analysis included: Fisher test on basal values; percent increase, difference between maximum and minimum values, absolute value after 8 hours and b coefficient of linear regression. Accuracy and sensitivity were evaluated for some of the data. Our results suggest that the activity of serum creatine kinase 8 hours after a quantified exercise can be useful to detect Duchenne muscular dystrophy carriers when basal activity is normal.