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Hemoglobin A1c (HbA1c) by High-Performance Liquid Chromatography (HPLC)

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

This test measures the average blood sugar (glucose) level over the past 2–3 months by examining the percentage of hemoglobin molecules that have sugar attached. It helps doctors assess long-term blood sugar control.

Quick summary

["HbA1c reflects your blood sugar trends over time, aiding diabetes management."]

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

Key facts at a glance

LOINC
71871-8
Short code
Hgb Barts MFr.DF Bld
Synonyms
Hgb Barts MFr.DF Bld
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85018
SNOMED
900000000000003004
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?

Unlike daily blood sugar checks, HbA1c gives a broader picture of how well your body manages glucose. It’s a key tool for doctors to adjust treatments and prevent complications like nerve damage or kidney issues.

How is this test done?

A small blood sample is taken from your arm, usually during a routine visit. The lab uses HPLC to separate and measure the different types of hemoglobin, including those with attached sugar.

What does a result mean?

Results are typically reported as a percentage (e.g., 5.7% or 6.4%). While exact ranges vary by lab, higher percentages often indicate poorer blood sugar control, while lower ones suggest better management.

Common reasons for testing

Doctors may order HbA1c to diagnose diabetes, monitor pre-existing conditions, or check for undiagnosed glucose issues. It’s also used during pregnancy to track gestational diabetes.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

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 involve?
You’ll have a small needle inserted into your arm to draw blood. The test itself takes about 10 minutes, but the blood draw may feel brief but might sting slightly. No special preparation is needed beyond fasting if your doctor specifies it.
How often should I get this test?
Your doctor will determine frequency based on your health. People with diabetes may check it every 3–6 months, while others with prediabetes might test annually.
Can lifestyle changes affect HbA1c results?
Yes! Improving diet, exercise, or managing stress can lower HbA1c over time. However, results may take weeks to reflect changes, so consistency is key.
  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