The CK ratio, specifically the CK-MB/CK ratio, is a clinical indicator used in laboratories, notably considered a diagnostic tool for Acute Myocardial Infarction (AMI).
The reference provided indicates that the CK-MB/CK ratio is a diagnostic indicator of AMI. It also states that the CK-MB/CK ratio in patients with malignancies was found to be significantly higher than in patients without malignancies.