HbA1C conversion chart

Glycated hemoglobin test, also known as HbA1C or A1C, is a blood test that shows you your average blood sugar level over the past 3-4 months.

It is a routine test in people already diagnosed with diabetes to monitor their treatment and suggest the need to better control their diet or adjust medications. HbA1C test may be used also to diagnose diabetes in patients suspected to have it.

What is HbA1C?

Glycated hemoglobin is a type of hemoglobin, the protein rich in iron found on red blood cells that allows to bind oxygen and transport it in the blood stream, that undergoes a chemical process known as glycosilation. The amount of hemoglobin that undergoes this transformation depends upon the amount of glucose available in the blood stream over the red blood cell lifespan, which is 120 days on average. For this reason, A1C is not affected by short term variation in blood sugar such as those induced by food intake, medications, stress or exercise.
Glycosilation is a non-easily reversible chemical process so a recent variation of the diet or change in the treatment plan won’t be reflected by HbA1C values until after several weeks due to the 4-months life span of RBCs.

HbA1C to mmol/L and mg/dL Conversion Chart

HbA1C to average blood glucose level conversion chart

HbA1C (%)	mmol/L	mg/dL	HbA1C (%)	mmol/L	mg/dL	HbA1C (%)	mmol/L	mg/dL
4.0	3.8	68	6.0	6.9	125	8.0	10.2	183
4.1	3.9	71	6.1	7.1	128	8.2	10.5	189
4.2	4.1	74	6.2	7.3	131	8.4	10.8	194
4.3	4.3	77	6.3	7.4	134	8.6	11.1	200
4.4	4.4	80	6.4	7.6	137	8.8	11.4	206
4.5	4.6	82	6.5	7.8	140	9.0	11.8	212
4.6	4.7	85	6.6	7.9	143	9.2	12.0	217
4.7	4.9	88	6.7	8.1	146	9.4	12.4	223
4.8	5.1	91	6.8	8.2	148	9.6	12.7	229
4.9	5.2	94	6.9	8.4	151	9.8	13.0	235
5.0	5.4	97	7.0	8.5	154	10.0	13.3	240
5.1	5.6	100	7.1	8.7	157	10.2	13.6	246
5.2	5.7	103	7.2	8.9	160	10.4	13.9	252
5.3	5.8	105	7.3	9.0	163	10.6	14.2	258
5.4	6.0	108	7.4	9.2	166	10.8	14.6	263
5.5	6.2	111	7.5	9.4	169	11.0	14.9	269
5.6	6.3	114	7.6	9.5	171	11.5	15.7	283
5.7	6.5	117	7.7	9.7	174	12.0	16.5	298
5.8	6.7	120	7.8	9.8	177	12.5	17.3	312
5.9	6.8	123	7.9	10.0	180	13.0	18.1	326

Values in RED cells indicate poor diabetic control. (>9% A1C)
Values in YELLOW cells indicate fair diabetic control (8% to 9% A1C)
Values in GREEN-YELLOW cells indicate good diabetic control (<7% A1C)
Values in GREEN cells indicate expected results from non-diabetic individuals. (4% to 5.9% A1C)

To convert from UK standard unit (mmol/L) to US standard unit (mg/dL) please check this page.

Conversion from old units (NGSP or HbA1C %) to new units (IFCC or mmol/mol)

In the past 15 years, to report the results from the glycated hemoglobin test a new unit has been proposed and introduced . Some countries already adopted the new unit in their lab reports, while others still stick to the old unit or use both.

While the results reported are the same, the numbers differ substantially and can create confusion. Here below you can find the conversion table from NGSP to IFCC units.

HbA1C % to mmol/mol conversion chart

NGSP (HbA1C %) to IFCC (mmol/mol) standard conversion chart for glycated hemoglobin test

HbA1C (%) - NGSP	mmol/mol - IFCC	HbA1C (%) - NGSP	mmol/mol - IFCC	HbA1C (%) - NGSP	mmol/mol - IFCC
4.0	20	6.0	42	8.0	64
4.1	21	6.1	43	8.2	66
4.2	22	6.2	44	8.4	68
4.3	23	6.3	45	8.6	70
4.4	25	6.4	46	8.8	73
4.5	26	6.5	48	9.0	75
4.6	27	6.6	49	9.2	77
4.7	28	6.7	50	9.4	79
4.8	29	6.8	51	9.6	81
4.9	30	6.9	52	9.8	84
5.0	31	7.0	53	10.0	86
5.1	32	7.1	54	10.2	88
5.2	33	7.2	55	10.4	90
5.3	34	7.3	56	10.6	92
5.4	36	7.4	57	10.8	95
5.5	37	7.5	58	11.0	97
5.6	38	7.6	60	11.5	102
5.7	39	7.7	61	12.0	108
5.8	40	7.8	62	12.5	113
5.9	41	7.9	63	13.0	119

Sources

Mosby’s Diagnostic and Laboratory Test Reference.
K Pagana – Elsevier, 2018
ISBN: 978-0-323-60969-2
Guide to Diagnostic Tests, 7th Ed.
D. Nicoll – McGraw-Hill, 2017
ISBN: 978-1-25-964090-2
American Diabetes Association (ADA)
UK National Health Service (NHS)