Useful Table for Those Dealing with Diabetes

[furrbear]

Cross-posted in diabetic_bears:

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Hb-A1c to Mean Plasma Glucose Conversion Table
(in mg/dl and mmol/l)

Hb-A1c	4.0	4.1	4.2	4.3	4.4	4.5	4.6	4.7	4.8	4.9
mg/dl	65	69	72	76	79	83	86	90	93	97
mmol/l	3.6	3.8	4.0	4.2	4.4	4.6	4.8	5.0	5.2	5.4
Hb-A1c	5.0	5.1	5.2	5.3	5.4	5.5	5.6	5.7	5.8	5.9
mg/dl	101	104	108	111	115	118	122	126	129	133
mmol/l	5.6	5.8	6.0	6.2	6.4	6.6	6.8	7.0	7.2	7.4
Hb-A1c	6.0	6.1	6.2	6.3	6.4	6.5	6.6	6.7	6.8	6.9
mg/dl	136	140	143	147	151	154	158	161	165	168
mmol/l	7.6	7.8	8.0	8.2	8.4	8.6	8.8	9.0	9.2	9.4
Hb-A1c	7.0	7.1	7.2	7.3	7.4	7.5	7.6	7.7	7.8	7.9
mg/dl	172	176	180	183	186	190	193	197	200	204
mmol/l	9.6	9.8	10.0	10.2	10.4	10.6	10.8	11.0	11.2	11.4
Hb-A1c	8.0	8.1	8.2	8.3	8.4	8.5	8.6	8.7	8.8	8.9
mg/dl	207	211	215	218	222	225	229	232	236	240
mmol/l	11.6	11.8	12.0	12.2	12.4	12.6	12.8	13.0	13.2	13.4
Hb-A1c	9.0	9.5	10.0	10.5	11.0	11.5	12.0	12.5	13.0	13.5
mg/dl	243	261	279	297	314	332	350	368	386	403
mmol/l	13.6	14.6	15.6	16.6	17.5	18.5	19.5	20.4	21.4	22.4

Note: The table to convert Hb-A1c to Mean Plasma Glucose (MPG) is based on the following formulas:

HbA1c = (Mean Plasma Glucose mg/dl + 77.3) / 35.6
HbA1c = (Mean Plasma Glucose mmol/l + 4.29) / 1.98

Mean Plasma Glucose mg/dl = (HbA1c x 35.6) - 77.3)
Mean Plasma Glucose mmol/dl = (HbA1c x 1.98) - 4.29

(To convert from mg/dl to mmol/l, divide mg/dl by 18...
or multiply mmol/l by 18 to get mg/dl)

The formulae were calculated by linear regression analysis, which is a mathematical way to predict a point based on known points. The data were obtained by analyzing the results from 1439 subjects enrolled in the Diabetic Control and Complications Trial (DCCT). Correlation between HbA1c and Mean Plasma Glucose (MPG) is not "perfect" but rather only .81 (1.0 would be a straight line, which has "perfect" correlation...) This means that to predict or estimate average glucose from Hb-A1c or vice-versa is not "perfect" but gives a good working ballpark estimate. Afternoon and evening results correlate more closely to HbA1c than morning results, perhaps because morning fasting glucose levels vary much more than daytime glucose levels, which are easier to predict and control.

The formulas are more accurate for adults than for infants or young children. They are not as valid for persons that have blood disorders or different hemoglobin composition other than what is "normal" for adults. If your average blood glucose results over a three month period do not coincide with the values above (plus or minus 15%) then you should get an additional blood test called Hemoglobin Electrophoresis which might disclose the presence of sickle cell anemia or other blood disorder.

Blood glucose measured in a laboratory spins red blood cells out of the sample, leaving only plasma. Blood glucose measured in a home glucose meter uses capillary blood, which has a different concentration of glucose. Virtually all new home glucose meters and test strips are callibrated to yield a plasma glucose value, so results should be close to lab readings taken at the same time, but can vary by up to 15%.

Therefore: Use the above table only as a useful tool to have a rough idea of what your average blood glucose was, if you don't already know it.