Methods, units and quality requirements for the analysis of haemoglobin A1c in diabetes mellitus

Table 4 The relationships between the hemoglobin A_1c units as % values to the mmol/mol values are presented at different levels of hemoglobin A_1c

HbA1c	HbA1c	HbA1c
	(%)	(mmol/mol)
Reference limits	4.0-6.0	20-42
Diagnosis limit	6.5	48
Treatment limits, adults	7.0	53
children < 6 yr	7.5	69
children 6-12 yr	8.0	64
children 13-19 yr	8.5	58
Poor diabetic balance	9.0	75
Very poor diabetic balance	12.0	108

Equarions from the NGSP/DCCT mean values to the IFCC units: % = 0.095 × mmol/mol + 2.15; mmol/mol = 10.93 × % - 23.5. The table also shows the most important equations to convert the results described in % units of NGSP/DCCT into the values of IFCC expressed as mmol/mol units[23]. HbA_1c: Hemoglobin A_1c; NGSP/DCCT: National Glycohemoglobin Standardization Program/the Diabetes Control and Complicatioins Trial Research Group; IFCC: International Federation of Clinical Chemistry.