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Hemoglobin A1c (HbA1c) measured 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, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

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

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

Key facts at a glance

LOINC
35473-8
Short code
HEXA 7.6kb Del Bld/T Ql
Synonyms
HEXA 7.6kb Del Bld/T 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

What HbA1c Tests Measure

HbA1c reflects the amount of glucose (sugar) that has attached to hemoglobin, the protein in red blood cells that carries oxygen. This attachment is a stable marker of your blood sugar levels over time, providing insight into how well your body manages glucose over months rather than just days.

How HbA1c Works

The test uses high-performance liquid chromatography (HPLC) to separate and measure hemoglobin variants, including HbA1c. This method is precise and avoids interference from other factors that might affect simpler testing methods.

Why HbA1c Matters

Unlike daily blood sugar checks, HbA1c gives a broader picture of your glucose control. It’s particularly useful for diagnosing diabetes, assessing treatment effectiveness, and identifying trends in blood sugar levels that may not be obvious from spot checks.

How Often Is This Test Done?

HbA1c is typically checked every 3 to 6 months for people with diabetes to monitor progress with treatment plans. Your healthcare provider may recommend more frequent testing if your blood sugar levels are unstable or if you’re adjusting medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

How does HbA1c help doctors diagnose diabetes?
HbA1c is a key diagnostic tool for diabetes. A result of 6.5% or higher on two separate tests suggests you have diabetes. It helps rule out diabetes by showing consistently normal blood sugar levels over time, even if recent blood tests appear normal.
What does an elevated HbA1c mean?
An elevated HbA1c (typically 6.5% or higher) indicates poor blood sugar control and may signal diabetes or prediabetes. It can also reflect other conditions like kidney disease or certain medications that affect hemoglobin. Your doctor will discuss next steps based on your results.
Can HbA1c be affected by other health conditions?
Yes, conditions like kidney disease, anemia, or certain medications (e.g., some blood thinners or chemotherapy drugs) can affect HbA1c levels. If your results seem unusual, your doctor may order additional tests to investigate further.
  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