scope:

This document presents information on the rationale for harmonization of glycohemoglobin testing among clinical laboratories. The process is described by which the NGSP has established, on a large scale, comparability of GHB test results among laboratories to a common reference. The reference values are, in turn, indexed to clinical outcomes data. The document also includes information about the structure of the laboratory network which is the backbone of the harmonization program, as well as procedures for monitoring the network, for testing and certifying manufacturers' assay methods and laboratories, and for monitoring the effectiveness of the program by proficiency testing of routine clinical laboratories. The information is designed to facilitate participation in the NGSP by manufacturers of GHB testing methods and materials, as well as routine clinical laboratories. This document also includes information on clinical application of GHB testing results and should be useful to both laboratorians and healthcare providers involved in the care of patients with diabetes mellitus, as well as to individuals and organizations involved in quality assurance programs for patients with diabetes mellitus. In addition, this document is a starting point for discussion regarding development of a universal harmonization program for GHB.

While C44-A may serve as a useful resource for a wider audience, it is intended for use primarily in the United States.