Which reaction type characterizes the Oliver-Rosalki CK determination method?

• A. Reverse reaction
• B. Forward reaction
• C. Both reverse and forward
• D. Neither

Answer: (A)

The test hinges on the fact that creatine kinase catalyzes a reversible reaction: ATP + creatine ⇌ phosphocreatine + ADP. In the Oliver‑Rosalki determination, the assay is set up to drive CK in the reverse direction (ATP and creatine forming phosphocreatine and ADP). The ADP produced is immediately used by pyruvate kinase in a coupled reaction with phosphoenolpyruvate to make pyruvate and ATP, and the pyruvate is then reduced to lactate by lactate dehydrogenase, which consumes NADH. By monitoring the rate of NADH disappearance, you quantify how fast ADP is produced, which directly reflects CK activity in the reverse direction. This coupling is the hallmark of the Oliver‑Rosalki method, making the reverse reaction the best description of how the assay works in practice.