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Hemoglobin A1c (HbA1c) with high-performance liquid chromatography (HPLC) measurement

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 control and long-term blood sugar trends."]

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

Key facts at a glance

LOINC
77481-0
Short code
Deprecated Hind+Mid ft-Bl XR 2V
Synonyms
Deprecated Hind+Mid ft-Bl 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 for Diabetes Management

HbA1c is a key tool for managing diabetes because it provides a snapshot of how well your blood sugar has been controlled over time. Unlike daily blood glucose checks, it gives a broader picture, helping prevent complications like nerve damage or kidney disease.

How the Test Works

Your blood sample is analyzed using high-performance liquid chromatography (HPLC), a precise method that separates hemoglobin types based on their sugar content. The test measures the proportion of hemoglobin A1c relative to total hemoglobin.

What the Results Mean

Results are typically reported as a percentage (e.g., 6.5%). Higher percentages indicate poorer blood sugar control, while lower percentages suggest better management. However, individual reference ranges may vary by lab.

Common Causes of Abnormal Results

Elevated HbA1c may signal uncontrolled diabetes, while lower levels could indicate recent blood sugar fluctuations or certain medical conditions. Rarely, lab errors or hemoglobin disorders may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c (HPLC)

Frequently asked questions

How often should I get this test?
For people with diabetes, HbA1c is usually checked every 3–6 months. Your doctor may adjust frequency based on your blood sugar goals and overall health.
Does diet or exercise affect HbA1c results?
Yes! Improving diet, exercise, or medication adherence can lower HbA1c over time. However, results take weeks to reflect changes, so consistency matters more than short-term fluctuations.
Can HbA1c be affected by pregnancy?
Yes, pregnancy can temporarily alter HbA1c levels due to hormonal changes. Some labs may adjust interpretation for pregnant individuals, so discuss results with your healthcare provider.
  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