Blood sugar tests

Explore glucose and HbA1c, the units labs use and the different periods these tests measure.

Explore blood sugar

HbA1c and fasting glucose: a three-month average and a single moment

One is a snapshot of the morning you gave blood, the other reflects roughly three months. Why they can disagree, and what the estimated average glucose row is.

Read the guide

Test explainer

Fasting Glucose

Reported in mg/dL · mmol/L.

Test explainer

Postprandial Glucose

Reported in mg/dL · mmol/L.

Test explainer

HbA1c

Reported in % · mmol/mol.

Test explainer

Estimated Average Glucose

Reported in mg/dL.

Reading the report

Guide

What the H and L flags on a lab report actually assert

A flag compares your number to the range printed beside it on that page — nothing more. What it does not tell you, and why healthy people collect them.

Guide

Why the same blood test has different "normal" ranges at different labs

Reference intervals are built from each lab's own population and equipment, which is why two labs can print different ranges for the same sample.

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