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

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

This blood 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 control and long-term blood sugar trends."]

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

Key facts at a glance

LOINC
75729-4
Short code
HTR2A c.1354C>T Bld/T Ql
Synonyms
HTR2A c.1354C>T Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
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

Why is HbA1c important?

HbA1c provides a snapshot of your blood sugar management over time, which can help prevent complications like nerve damage, kidney disease, or heart problems. Unlike daily blood sugar checks, it gives a broader picture of how well your treatment plan is working.

How is HbA1c tested?

A small blood sample is taken from your arm and analyzed using high-performance liquid chromatography (HPLC), a precise method that separates and measures hemoglobin variants, including those with sugar attachments.

What does an HbA1c result mean?

Results are reported as a percentage (e.g., 5.7%–6.4% may indicate prediabetes, while 6.5% or higher often signals diabetes). Your doctor will interpret results in the context of your overall health and treatment goals.

How often should HbA1c be checked?

Regular HbA1c testing is recommended every 3–6 months for people with diabetes or prediabetes to monitor progress and adjust treatments as needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

What does an HbA1c test measure?
It measures the proportion of hemoglobin molecules that have attached glucose (sugar) over the past 2–3 months, reflecting your average blood sugar levels.
Can HbA1c be affected by other conditions?
Yes, conditions like anemia, kidney disease, or certain medications (e.g., blood thinners) can influence HbA1c results. Your doctor may order additional tests if needed.
Is HbA1c the same as a fasting blood sugar test?
No, HbA1c is different—it measures long-term sugar attachment to hemoglobin, while fasting blood sugar tests check current blood sugar levels after fasting.
  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