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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 track long-term diabetes control and is a key indicator of blood sugar management."]

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

Key facts at a glance

LOINC
11928-9
Short code
GA from GSD.Hellman69
Synonyms
GA from GSD.Hellman69
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-gsd-hellman
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is HbA1c Used For?

HbA1c is primarily used to diagnose diabetes, assess long-term blood sugar control, and monitor treatment effectiveness in people with diabetes. It provides a snapshot of your average glucose levels over time, which can help doctors adjust medications or lifestyle strategies.

How Is HbA1c Different from Daily Blood Sugar Checks?

Unlike daily fingerstick glucose tests, HbA1c gives a broader picture by measuring the percentage of hemoglobin linked to glucose. This test doesn’t show immediate spikes or drops but instead reflects trends over months, making it useful for long-term planning.

Why Is HbA1c Important for People Without Diabetes?

Even without diabetes, HbA1c can indicate prediabetes or early glucose control issues. Regular monitoring helps prevent complications like heart disease or nerve damage by catching subtle trends early.

How Is HbA1c Tested?

This test uses a small blood sample (usually from your arm) and analyzes it via high-performance liquid chromatography (HPLC), a precise method that separates hemoglobin types based on their sugar content.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c is a gold-standard test for diabetes diagnosis (typically ≥6.5% confirms diabetes) and guides treatment decisions. Lower-than-target HbA1c levels (e.g., <7%) suggest good control, while higher levels may signal the need for dietary changes, medication adjustments, or closer monitoring.

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
If you have diabetes, your doctor may recommend testing every 3–6 months. For prediabetes or pre-diabetes risk, testing every 1–2 years may suffice, but individual needs vary based on health status.
Does HbA1c change if I’m pregnant?
Yes, HbA1c can be slightly lower during pregnancy due to hormonal shifts affecting glucose metabolism. Your doctor may adjust testing frequency or timing to ensure accurate results.
Can lifestyle changes affect HbA1c results?
Absolutely. Improvements in diet, exercise, or weight loss can lower HbA1c levels over time, while poor control (e.g., high sugar intake) may raise it. Results reflect your recent habits, so consistency matters.
  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