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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 (glycated hemoglobin), 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
30351-1
Short code
Hgb BldMV-mCnc
Synonyms
Hgb BldMV-mCnc
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 this test important?

Measuring HbA1c is crucial for diagnosing diabetes and assessing how well your blood sugar is managed over time. Unlike daily blood sugar checks, it provides a broader picture of your metabolic health.

How is the test performed?

A small blood sample is taken from your arm, typically during a routine visit to your healthcare provider. The sample is analyzed using high-performance liquid chromatography (HPLC) to determine the glycated hemoglobin percentage.

What does the result mean?

Results are reported as a percentage (e.g., 5.7%, 6.4%, 7.5%). Higher percentages indicate poorer blood sugar control, while lower percentages suggest better management. However, reference ranges can vary by lab and individual health status.

Who might need this test?

Healthcare providers may recommend HbA1c testing for people with diabetes, those at risk for diabetes, or individuals with symptoms like frequent urination, excessive thirst, or unexplained weight changes.

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

How often should I get this test?
Typically, people with diabetes are advised to get HbA1c tested every 3–6 months to track progress. Your doctor will determine the frequency based on your specific needs and health status.
What can affect my HbA1c results?
Several factors, including recent blood loss, severe illness, or certain medications (like some blood pressure drugs), can temporarily alter HbA1c levels. It’s important to discuss any recent changes in health or medications with your provider.
Do I need to prepare for this test?
No special preparation is usually needed, but you may be asked to avoid certain medications (like some blood pressure drugs) or foods (like high-protein diets) for a short period before testing, depending on your doctor’s instructions.
  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