Activity of creatine kinase in sera from healthy women, carriers of Duchenne muscular dystrophy and cord blood, determined by the "European" recommended method with NAC-EDTA activation.

Creatine kinase activity has been measured at 37 degrees C in sera from healthy women, carriers of Duchenne muscular dystrophy and cord blood, with activation by N-acetyl cysteine (NAC) and EDTA as recommended by several European committees on standardisation. The upper limit of the reference range for healty women was found to be 170 U/l. The distributions of creatine kinase activities in healthy and carrier women have been used to calculate probability of carrier status as a function of creatine kinase activity. Although the range of creatine kinase activities in normal cord blood is wide, the data provide a basis for interpretation when Duchenne muscular dystrophy is suspected.