It is based on using regression analysis on published tables provided by doctors as follows:

A1C 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00

BSR 126 140 154 169 183 197 212 226 240

I rounded off the regression coefficients to make its easy for any user to relate the A1C to the Blood Sugar Reading (BSR). The resulting regression line had 0.999 correlation (very strong).

I would argue that certain limitations are to be considered here. A1C estimation should not be obtained by a single measure of BSR, especially in patients under hypoglycemic therapy given the high variability in measurements. It would be better after an average number of fasting readings per week. Second, even if fasting glycemia is normal, some subjects might have impaired postprandial glycemia, which might not show initially in fasting measurements and might abnormally show these estimations. Finally, A1C estimation usually is helpful estimating average glucose levels and I am not sure whether estimating it backwards could have meaningful impact in reducing disease burden. I believe you could solve these problems by showing that your estimator adequately correlates to measured A1C in an independent sample for validation and that these observation holds for both fasting and postprandial measurements or, even better, adjust a formula for each under standardized conditions.

Thank you for your comments. I agree with you.

Dr Bello makes a good point about limitations. I would support you pursuing additional sampling in varied conditions, fasting, postprandial etc. A time series analysis would be useful. I think your concept has utility for patients to use as a quick feedback tool, since their provider is using longer term data of the A1c (which I appreciate you are not discarding). The more often a patient gets useful feedback, the more opportunities to reflect and perhaps feel motivated to take corrective action.

Thank you and I agree that this equation isn’t a substitute for the A1C but it does provide users a quick check on the blood sugar level. If the user is to collect blood sugar readings over a period of time, as you had suggested, then the equation provides a more accurate reading on the A1C. It is meant for people who are unable to obtain the A1C due to cost and/or other factors.

Dear All, thank you for making good points.

I advent published it yet. My intent is to provide people who can't afford the A1C test with the means to at least get some information on their A1C.

Different formulas have been devised to equate the HbA1c to the blood glucose. However, these formulas are only meant to help the lay patients to give a rough idea whether their diabetes is controlled or uncontrolled.

These formulas are not always helpful and will not replace the target HbA1c levels (6.5 - 7.0%) that have been shown to prevent the diabetic complications and have been recommended by different guidelines on diabetes mellitus.

One such formula is

What is HbA1c? - Definition, Units, Conversion ... - Diabetes.co.uk

Another converter is:

https://www.hba1cnet.com/hba1c-calculator/

Agree with Muhammad Yousuf comment.

The Hemoglobin A1c (HbA1c or simply A1c for short) test is a blood test used to measure the average blood glucose concentration in your body in the past 1-3 months. For diabetics, this is the standard way of determining how well the diabetes is controlled. An A1c of less than 7% is considered good.

Getting the test every 3 months (usually during a doctor visit) is usually enough. But sometimes you may want to just estimate your A1c level based on the data from your regular self-tests. The formula below could help in this case.

Accuracy, of course, could vary depending on how often and when you check your blood sugar. I found it pretty accurate last time I used it. My calculation was off only by 0.1%. This is the same formula GlucoseTracker uses in the app's dashboard.

Glucose in mg/dL:

A1c = (46.7 + average_blood_glucose) / 28.7

Glucose in mmol/L:

A1c = (2.59 + average_blood_glucose) / 1.59

So, for example, if your average blood glucose level in the past 3 months is 130 mg/dL (7.2 mmol/L) , your estimated A1c is 6.15%