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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 level of hemoglobin A1c in your blood over the past 2–3 months, reflecting your blood sugar control.

Quick summary

["HbA1c helps doctors assess long-term diabetes management and adjust treatment plans."]

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

Key facts at a glance

LOINC
93846-4
Short code
Hgb BldV-sCnc
Synonyms
Hgb BldV-sCnc
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

What HbA1c Measures

HbA1c is a form of hemoglobin (the protein in red blood cells that carries oxygen) that has been attached to sugar (glucose) from your blood. This test quantifies how much of your hemoglobin is bound to glucose, giving a snapshot of your blood sugar levels over time.

Why It’s Used

Doctors use HbA1c to diagnose diabetes, monitor diabetes treatment effectiveness, and detect long-term complications like nerve damage or kidney issues. It’s especially useful because it accounts for fluctuations in daily blood sugar levels.

How It’s Performed

A small blood sample is taken from your arm, usually during a routine visit. The sample is processed using HPLC to separate and measure hemoglobin variants, including HbA1c.

What to Expect Before or After

No special preparation is needed. You may feel slight discomfort from the needle, but it’s brief. Results are typically ready within a few days and shared with your healthcare provider.

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 abnormal HbA1c result mean?
An abnormal HbA1c result may signal poor blood sugar control, diabetes, or prediabetes. Your doctor will discuss your results in detail and recommend lifestyle or treatment adjustments if needed.
How often should I get an HbA1c test?
If you have diabetes, your doctor may recommend HbA1c testing every 3–6 months to track progress. If you’re prediabetic or at high risk, testing may be less frequent but still important for early intervention.
Can lifestyle changes affect HbA1c results?
Yes! Regular physical activity, a balanced diet, and weight management can lower HbA1c levels. Small, sustainable changes often yield the best long-term results.
  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