Master Equations

The national programs for the harmonization of HbA1c in the US (National Glycohemoglobin Standardization Program; NGSP), Japan (Japanese Diabetes Society/Japanese Society of Clinical Chemistry; JDS/JSCC), and Sweden (Mono-S) are based on different designated comparison methods (DCMs). The master equations to convert DCM units into IFCC units and vice versa have been established by the IFCC network (Reference). The validity of the Master Equations of NGSP and JDS/JSCC is monitored twice a year by the laboratories.

The list of DCM Laboratories monitoring the Master Equations is under the button DCMs.
Conversion IFCC- to DCM-units Conversion DCM-units into IFCC-units
NGSP = 0.0915*IFCC + 2.15 % IFCC = 10.93*NGSP – 23.5 mmol/mol
JDS/JSCC = 0.0927*IFCC + 1.73 % IFCC = 10.79*JDS/JSCC – 18.7 mmol/mol
Mono S = 0.0989*IFCC + 0.88 % IFCC = 10.11*Mono S – 8.9 mmol/mol

Hoelzel W, Weykamp C, Jeppsson JO, Miedema K, Barr JR, Goodall I, Hoshino T, John WG, Kobold U, Little R, Mosca A, Mauri P, Paroni R, Susanto F, Takei I, Thienpont L, Umemoto M, Wiedmeyer HM. IFCC Reference System for Measurement of hemoglobin A1c in human blood and the national standardization schemes in the United States, Japan and Sweden:  a method comparison study. Clin Chem 2004;50:166-74