Standardization in Clinical Enzymology

The goal of standardization in Laboratory Medicine is to achieve comparable results in human samples, independent of the reagent kits, instruments, and laboratory where the assay is carried out. To pursue this objective in clinical enzymology, the IFCC has established reference measurement systems for the most important clinical enzymes. These systems are based on the following requirements: a) reference methods, well described in procedures that are extensively evaluated; b) suitable reference materials; and c) reference laboratories operating in a highly controlled manner. Using these reference systems and the manufacturer's standing procedures, industry can assign traceable values to commercial calibrators. Clinical laboratories, which use routine procedures with validated calibrators to measure enzymes in human specimens, can finally obtain values which are traceable to higher-order reference procedures. These reference systems constitute the structure of the traceability chain to which the enzyme routine methods can be linked via an appropriate calibration process, provided that they have a comparable specificity (i.e. they are measuring the same quantity).