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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 in your blood that is attached to sugar (glycated hemoglobin). It reflects your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA1c helps doctors track long-term diabetes control and identify trends in blood sugar management."]

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

Key facts at a glance

LOINC
55240-6
Short code
HBB c.251G>A Bld Ql
Synonyms
HBB c.251G>A Bld Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
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 This Test Matters

HbA1c is a key indicator of how well your body manages blood sugar over time. Unlike daily blood sugar checks, it provides a broader picture of your health, especially useful for people with diabetes or prediabetes.

How It Works

Blood is drawn and analyzed using high-performance liquid chromatography (HPLC), which separates hemoglobin types based on their sugar content. The test detects the proportion of hemoglobin that has sugar molecules attached.

Sample Collection

A small blood sample is taken from your arm, typically in a clinic or lab. You may feel a slight pinch, but it’s usually quick and not painful.

What to Expect Before the Test

No special preparation is needed, but inform your provider if you’re taking certain medications (like insulin or blood thinners) or have a recent illness, as these can affect results.

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?
Your doctor will determine frequency based on your diabetes status. People with diabetes may test every 3–6 months, while others with prediabetes might test annually.
What do my results mean?
Results are usually reported as a percentage (e.g., 5.7%–6.4% is prediabetes; ≥6.5% is diabetes). A lower percentage suggests better blood sugar control, while a higher percentage may signal the need for adjustments to diet, exercise, or medication.
Can diet or exercise affect this test?
Yes! While HbA1c reflects long-term trends, short-term lifestyle changes (like diet or exercise) can influence blood sugar levels over time. Consistency matters more than short-term fluctuations.
  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