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Hemoglobin A1c (HbA1c) with mass concentration measurement

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

This test measures the average blood sugar level over the past 2–3 months by analyzing your red blood cells. It helps doctors assess long-term blood glucose control.

Quick summary

["HbA1c 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
22315-6
Short code
HAV IgM Ser-aCnc
Synonyms
HAV IgM Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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

What HbA1c Tests Measure

HbA1c is formed when hemoglobin binds to excess glucose in your blood. Over time, this creates a stable compound that remains in red blood cells. The test quantifies this compound to estimate your average blood sugar levels during the preceding 2–3 months, accounting for daily fluctuations.

Why It’s Used in Diabetes Care

HbA1c is a key tool for diagnosing diabetes (when levels are ≥6.5%) and monitoring treatment effectiveness. Unlike daily blood sugar checks, it provides a broader picture of how well your body manages glucose over time.

How the Test Works

Blood is drawn from a vein, typically in your arm. The sample is processed to separate hemoglobin from other blood components, then analyzed to determine the proportion of hemoglobin bound to glucose.

Sample Collection and Preparation

A small amount of blood is taken from your arm using a needle. The sample is sent to a lab where it’s tested using automated methods to measure the HbA1c percentage.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

What does an abnormal HbA1c result mean?
An HbA1c result above 6.5% may indicate diabetes or prediabetes. Lower results (below 5.7%) suggest good blood sugar control, while values between 5.7%–6.4% may warrant further monitoring.
Can HbA1c results change over time?
Yes, HbA1c levels can shift due to diet, exercise, medications, or underlying health conditions. Regular testing helps track trends and adjust treatment plans as needed.
Does HbA1c differ between men and women?
No, HbA1c is measured the same way regardless of gender. However, some studies suggest slight variations in average levels may exist due to differences in hemoglobin composition or lifestyle factors.
  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