Skip to content

Hemoglobin A1c (HbA1c) Mass Concentration in Whole Blood

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 your red blood cells.

Quick summary

["HbA1c reflects long-term blood sugar control, helping doctors assess diabetes management."]

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

Key facts at a glance

LOINC
47861-0
Short code
HPRT Amnc-cCnt
Synonyms
HPRT Amnc-cCnt
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Does HbA1c Measure?

HbA1c is a form of hemoglobin (the protein in red blood cells that carries oxygen) that has been bonded to glucose. It serves as a snapshot of your blood sugar levels over time, accounting for fluctuations that daily measurements might miss.

Why Is HbA1c Important?

This test is critical for diagnosing diabetes and monitoring how well your blood sugar is controlled. It helps prevent complications by identifying trends in glucose levels that might not be apparent from single blood sugar checks.

How Is HbA1c Tested?

Your blood sample is collected, typically from a fingerstick or vein, and analyzed using an immunoassay method to measure the percentage of hemoglobin bound to glucose.

What Are Common HbA1c Results Used For?

Results are used to classify diabetes status (e.g., prediabetes, type 1 or type 2 diabetes) and guide treatment plans, such as diet, medication, or lifestyle adjustments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c levels are clinically significant because they provide a reliable indicator of glycemic control. Low levels may suggest poor diabetes management, while high levels indicate prolonged elevated blood sugar, increasing risks for long-term health issues like nerve damage, kidney problems, or cardiovascular disease.

Short name

HbA1c

Frequently asked questions

What Does an HbA1c Test Tell Me About My Health?
An HbA1c test tells you the average blood sugar level over the past few months, helping your healthcare provider assess whether your diabetes is well-controlled or if adjustments to your treatment plan are needed.
How Often Should I Get an HbA1c Test?
The frequency depends on your health status. Typically, people with diabetes are tested every 3–6 months, while those with prediabetes may need testing every 1–2 years unless advised otherwise.
Can HbA1c Levels Change Without Me Knowing?
Yes, HbA1c levels can change gradually due to diet, exercise, medications, or other health conditions. Regular testing helps catch trends early, so discuss any changes with your doctor.
  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