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Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)

Published: August 9, 2026Updated: August 17, 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 track long-term blood sugar control for diabetes management."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
33162-9
Short code
EFW from Hadlock 1991
Synonyms
EFW from Hadlock 1991
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-hadlock
CPT
82553
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 This Test Matters

HbA1c is a key indicator of how well your blood sugar has been controlled 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 processed to separate hemoglobin from other blood components. The test then uses HPLC to measure the proportion of hemoglobin molecules linked to glucose, which is expressed as a percentage.

Sample Collection

A small blood sample is taken from your arm, usually during a routine visit to your healthcare provider. The sample is sent to a lab for analysis.

What to Expect

You may feel a slight pinch when the needle is inserted, but the procedure is quick. Afterward, you can resume normal activities. No special preparation is needed, though fasting is not required.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

HbA1c levels help diagnose diabetes, monitor treatment effectiveness, and assess long-term blood sugar control. Higher levels may indicate poor management of diabetes or prediabetes, while lower levels might suggest overly aggressive treatment or other health conditions.
HbA1c levels are typically reported as a percentage (e.g., 5.7%–6.4% is considered prediabetes, while 6.5% or higher suggests diabetes). Your results will be interpreted in the context of your medical history and other health factors.
How often should I get this test?
The frequency depends on your health status. People with diabetes usually get HbA1c tested every 3–6 months to track progress. Your healthcare provider will determine the best schedule for you.
Can lifestyle changes affect my HbA1c results?
Yes! Regular physical activity, a balanced diet, and managing stress can help lower HbA1c levels. Consistently following your treatment plan—including medications and diet—can also 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 17, 2026. · Read our editorial policy