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Hemoglobin A1c (HbA1c) 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

["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
77461-2
Short code
Deprecated Hind+Mid ft XR 2V
Synonyms
Deprecated Hind+Mid ft XR 2V
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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

Why This Test Matters

Unlike daily blood sugar checks, HbA1c gives a broader picture of how well your blood sugar has been controlled over time. It’s a key tool for diagnosing diabetes and assessing treatment effectiveness.

How It’s Done

A small blood sample is taken from your arm and sent to a lab. High-performance liquid chromatography separates hemoglobin types, allowing precise measurement of HbA1c.

What to Expect

You’ll feel no pain from the blood draw, but you may experience slight discomfort. Results are typically ready within a few days. If you’re diabetic, this test is often done every 3–6 months.

Common Causes of Abnormal Results

Elevated HbA1c may indicate poor blood sugar control, diabetes, or conditions like kidney disease or anemia. Low levels could suggest strict dietary control or rare genetic factors.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c results help doctors adjust treatments, such as medication or diet, to improve long-term health outcomes. It’s especially important for people with type 1 or type 2 diabetes.

Short name

HbA1c

Frequently asked questions

How often should I get this test?
For most people with diabetes, HbA1c is checked every 3–6 months. Your doctor may recommend more frequent testing if your blood sugar is hard to control.
Does diet affect HbA1c results?
Yes, diet plays a big role. Eating balanced meals with protein, fiber, and healthy fats can help stabilize blood sugar, but HbA1c reflects long-term trends over months.
Can HbA1c be affected by pregnancy?
During pregnancy, HbA1c can be slightly lower due to hormonal changes, but it still tracks blood sugar control. Discuss results with your doctor, especially if you have gestational diabetes.
  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