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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 average level of blood sugar (glucose) over the past 2–3 months by examining the percentage of hemoglobin molecules that have sugar attached. It helps doctors assess long-term blood sugar control.

Quick summary

["HbA1c reflects your blood sugar levels over time and is key to managing diabetes."]

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

Key facts at a glance

LOINC
110824-0
Short code
HTLV I Ab Msmt Ser
Synonyms
HTLV I Ab Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 is HbA1c important?

Unlike daily blood sugar checks, HbA1c gives a broader picture of how well your body manages glucose. It’s especially useful for people with diabetes or prediabetes to track progress with treatments and adjust care as needed.

How is this test done?

A small blood sample is taken from your arm, usually during a routine visit to your healthcare provider. The sample is analyzed using HPLC, a precise method that separates and measures hemoglobin variants, including those with attached sugar.

What does a high or low HbA1c mean?

A higher HbA1c percentage generally indicates poorer blood sugar control, while a lower percentage suggests better management. However, individual results depend on factors like diet, activity, and medications.

How often should I get this test?

Healthcare providers typically recommend HbA1c testing every 3–6 months for people with diabetes to monitor trends and make informed decisions about treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c is clinically significant because it provides a reliable, objective measure of glycemic control. It helps doctors diagnose diabetes, evaluate treatment effectiveness, and identify risks for complications like nerve damage or kidney disease.

Short name

HbA1c

Frequently asked questions

What causes changes in HbA1c levels?
Changes in HbA1c can result from diet, physical activity, medications (like insulin or oral diabetes drugs), stress, illness, or other health conditions. Consistent monitoring helps identify patterns or triggers.
Does diet affect HbA1c results?
Yes, diet plays a major role. Eating balanced meals with fiber, lean proteins, and healthy fats, while limiting sugary foods and refined carbs, can help stabilize blood sugar levels and improve HbA1c.
Can I get an HbA1c test at home?
Some at-home kits are available, but they may not be as precise as lab tests. Always confirm results with your healthcare provider, as they may require follow-up testing or professional interpretation.
  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