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Whole Blood Hemoglobin A1c (HbA1c) by High-Performance Liquid Chromatography (HPLC)

Published: August 9, 2026Updated: August 16, 2026

This test measures the average blood sugar level over the past 2–3 months by examining your red blood cells. It helps doctors assess long-term blood glucose control, especially useful for managing diabetes.

Quick summary

["This test reflects your blood sugar trends over time, aiding diabetes management."]

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

Key facts at a glance

LOINC
11161-7
Short code
Wheat Bran IgE Qn
Synonyms
Wheat Bran IgE Qn
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 This Test Done?

Doctors order an HbA1c test primarily to diagnose diabetes (including type 1 and type 2) or to monitor long-term blood sugar levels in people already diagnosed. It’s also used to check if your current treatment plan is working effectively.

How Is the Test Performed?

A small blood sample is taken from your arm, usually by a healthcare professional. The sample is then analyzed using a specialized machine to measure the percentage of hemoglobin molecules coated with sugar.

What Do the Results Mean?

Results are reported as a percentage. While exact ranges vary by lab, higher percentages generally indicate poorer blood sugar control. Your doctor will interpret the result in the context of your medical history and treatment.

What Are Common Causes of Abnormal Results?

Abnormally high HbA1c levels may suggest uncontrolled diabetes, while low levels could indicate recent blood sugar fluctuations or certain medical conditions. Rarely, errors in testing or sample handling might affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: HbA1c is a gold-standard marker for diabetes management because it provides a snapshot of average blood sugar over time. It’s less affected by short-term fluctuations (like stress or illness) compared to daily glucose checks.

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test if I have diabetes?
Typically, people with diabetes should get an HbA1c test every 3–6 months, depending on their overall health and treatment goals. Your doctor will recommend a schedule tailored to your needs.
Can diet or exercise affect my HbA1c test results?
While diet and exercise influence your blood sugar levels, they don’t directly impact the HbA1c measurement itself. However, they play a key role in managing your overall blood sugar control.
What if my HbA1c is outside the normal range?
If your HbA1c is high, your doctor may adjust your diabetes medications, lifestyle recommendations, or monitor you more closely. If it’s low, they might investigate potential causes like recent illness or medication side effects.
  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