HbA1c
What it measures
Reported as a percentage (the NGSP standard used across India and the US) or in mmol/mol (the IFCC standard used in some other countries) — unlike most conversions on this page, the relationship between the two is not a simple multiplication but a fixed formula, because they are calibrated against different reference methods rather than just different units of the same scale.
HbA1c
| Category | Value |
|---|---|
| Normal | below 5.7% |
| Prediabetes | 5.7% – 6.4% |
| Diabetes | 6.5% or above |
The ADA requires the test be run by an NGSP-certified method. HbA1c reflects roughly the previous three months, so it is unreliable in anyone whose red cells turn over unusually fast or slow — including in several forms of anaemia and haemoglobin variants, which are not rare in India.
Source: American Diabetes Association, Standards of Care in Diabetes — 2026, Section 2
Reading it in a different unit
This lab reports HbA1c in %. Reports from other labs — especially ones using European or US-style formatting — sometimes use a different unit for the same measurement. The relationship between them:
| Reported unit | How it relates to % |
|---|---|
| mmol/mol | % = (mmol/mol × 0.0914997) + 2.15 |
Unit conversions verified against published molar masses and LOINC definitions. This is not a diagnostic reference — the normal range for any test is set by the laboratory that ran it and printed on your report.
Why this matters for tracking a trend
A value plotted next to earlier results only tells you something if every point is on the same scale. Two readings of the same test from two different labs, in two different units, can look like a dramatic change when nothing about your actual result changed — only the unit did. Converting to one scale before comparing is what keeps a trend line honest.
LOINC codes for this test: 17856-6, 4548-4, 59261-8.
General information about laboratory measurement, not medical advice. Whether a specific result is normal for you depends on your lab's reference range, your history and your doctor's judgement — not on this page.