Global and national harmonization and standardization of clinical laboratory testings: The example of HbA1c

The equivalent or harmonized test results between different clinical laboratories and methods are the main requirements in order to achieve the quality health care. In this context, global standardization studies have been carried out worldwide. The major goal of standardization is the harmonization of patient test results. Standardization is established according to metrological principles. Even if the reference system for analyte is established, the harmonization still may not be achieved. The interlaboratory comparison studies provide evidence-based knowledge about harmonized test results. This way is also useful for the harmonization of analytes which are not well defined and for which reference procedures are not available. The aim of our study is to open the discussion of the importance of the national harmonization system for the effective healthcare services in the context of the HbA(1c) interlaboratory comparison study performed. The studies and improvements on the global standardization and harmonization of clinical laboratory test results were reviewed; the global standardization of HbA(1c) study was summarized, and the results of the HbA(1c) interlaboratory comparison study performed in Turkey was discussed as an example for the national standardization and harmonization of a laboratory test. In our example study, the coefficients of variation between the laboratories for both normal and pathologic levels were found higher than the target value, while the bias values were found in the acceptable levels. Although our study provides some reliable findings, more interlaboratory comparison programs should be carried out, and the national harmonization system should be established for every relevant analyte