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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

["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
77476-0
Short code
Deprecated Hind+Mid ft-R XR Harris
Synonyms
Deprecated Hind+Mid ft-R XR Harris
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 HbA1c Matters for Diabetes Care

HbA1c is a key indicator of how well your diabetes is managed over time. Unlike daily blood sugar checks, it provides a snapshot of your average glucose levels, helping your healthcare team adjust treatments like insulin or medication if needed.

How the Test Works

This test uses high-performance liquid chromatography (HPLC) to separate and measure the different types of hemoglobin in your blood. The percentage of hemoglobin A1c (the sugar-coated form) is compared to your total hemoglobin to give the result.

Sample Collection and Preparation

A small blood sample is taken from your arm, usually by a healthcare professional. The blood is processed to separate the red blood cells, and the remaining plasma or serum is analyzed for HbA1c levels.

What to Expect Before the Test

No special preparation is needed for this test. You may have a light snack or drink as usual, but avoid smoking or caffeine before your appointment if instructed by your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c is essential for diagnosing diabetes (typically ≥6.5%) and monitoring long-term blood sugar control. It helps identify trends in hyperglycemia (high blood sugar) or hypoglycemia (low blood sugar) and guides treatment decisions to prevent complications like nerve damage, kidney disease, or heart problems.

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
Your doctor will determine how often you need HbA1c testing based on your diabetes management plan. Typically, people with diabetes check it every 2–4 months to track progress and adjust treatments as needed.
What do my HbA1c results mean?
Results are usually reported as a percentage. A result of 5.7%–6.4% may indicate prediabetes, while 6.5% or higher suggests diabetes. Your doctor will interpret results in the context of your overall health and treatment plan.
Can lifestyle changes affect HbA1c results?
Yes! Diet, exercise, weight management, and medication adherence can significantly impact HbA1c levels. Small, sustainable changes—like eating balanced meals or increasing physical activity—can improve your results over time.
  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