Study of the Stability of Creatine Kinase in Control Materials

We examined the stability of twelve control materials from different suppliers containing creatine kinase. The stability was assessed storing preparations at 4 degrees C, 27 degrees C and 37 degrees C and periodically measuring creatine kinase catalytic concentration. The activity was significantly greater when the lyophilized material was reconstituted with water at 4 degrees C as compared to 27 degrees C and 37 degrees C. All preparations tested showed good stability at 4 degrees C over a 72 hour period. We considered the suitability of tested control materials for quality-control purposes.