Creatine kinase values in amyotrophic lateral sclerosis.

Serum creatine kinase (CK1) values were recorded while or soon after the diagnosis of amyotrophic lateral sclerosis (ALS) was established in 140 of 217 (65%) consecutive patients seen in the Motor Neuron Disease Clinic at this center during a 5-year period. Second creatine kinase (CK2) determinations were recorded on 48 of 140 (34%) ALS patients later in the course of the disease. The mean CK1 and CK2 values (unit, times the upper limit of normal) were 1.22 (range, 0.1 to 3.0; median, 0.80) and 1.34 (range, 0.1-9.2; median, 0.80) (P=0.11, r=0.92, mean difference=28.2%). Of the 140 ALS patients, 58 (41%) (male:female ratio: 2.9:1.0) had elevated CK1 values ranging from 1.03 to 13.0 (mean, 2.21; median, 1.67). Twelve patients (8.6%) had CK1 values greater than 3.0. Mean CK1 values were significantly greater (P=0.001) in male (mean, 1.56) versus female (mean, 0.80) ALS patients, and significantly greater (P=0.009) in limb-onset (mean, 1.34) versus bulbar-onset (mean, 0.80) disease. CK1 values correlated poorly with and were not predictive of age of onset or survival.