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Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)

Published: August 9, 2026Updated: August 16, 2026

This test measures the percentage of hemoglobin that is coated with sugar, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA1c helps doctors track diabetes management and long-term blood sugar control."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
73946-6
Short code
JWH-200 Bld Ql
Synonyms
JWH-200 Bld Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What HbA1c Tests Measure

HbA1c is a form of hemoglobin (the protein in red blood cells that carries oxygen) that has been linked to glucose (sugar) through a chemical reaction. This test quantifies how much of your hemoglobin is in this modified form, providing a snapshot of your blood sugar trends over time.

Why It Matters for Diabetes Care

Unlike daily blood sugar checks, HbA1c gives a broader picture of your glucose control, helping prevent complications like nerve damage or kidney disease.

How It’s Done

A small blood sample is taken from your arm, usually during a routine visit. The sample is analyzed using HPLC to separate and measure hemoglobin variants, including HbA1c.

When You Might Need It

Doctors order HbA1c tests for people with diabetes to monitor treatment effectiveness, or for those at risk of diabetes (e.g., with prediabetes) to assess risk.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Elevated HbA1c (>6.5%) strongly indicates diabetes, while lower levels (below 5.7%) suggest normal glucose control. Values between 5.7%–6.4% may indicate prediabetes, prompting lifestyle or medical interventions.

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
Typically, people with diabetes get an HbA1c test every 3–6 months to track progress. Your doctor may adjust frequency based on your treatment plan.
What do my HbA1c results mean?
Results are interpreted in context with your symptoms, diet, and medications. A doctor will explain what your specific percentage means for your health.
Can HbA1c results change if I’ve recently had a blood sugar spike?
Yes, HbA1c reflects long-term trends, so recent spikes (e.g., from illness or poor diet) won’t immediately alter your result. It takes about 2–3 months for new levels to reflect in the test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy