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Hemoglobin A1c (HbA1c) Glycated Hemoglobin

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

This test measures the percentage of hemoglobin in your blood that is attached to sugar (glycated hemoglobin), reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

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

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

Key facts at a glance

LOINC
41995-2
Short code
HbA1c Bld-mCnc
Synonyms
HbA1c Bld-mCnc
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4
Ref high
5.6
Critical range
2 N/A – 14 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83037
SNOMED
43387009
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

Why is this test important?

HbA1c is a key indicator of how well your blood sugar has been controlled over time. Unlike daily blood sugar checks, it provides a broader picture of your health, helping prevent complications like nerve damage, kidney disease, or vision problems.

How is this test performed?

A small blood sample is taken from your arm, usually during a routine blood draw. The test measures the proportion of hemoglobin molecules that have sugar molecules attached, which is then converted into a percentage.

What does a result mean?

Results are typically reported as a percentage (e.g., 5.7%, 6.5%, or 7.9%). While exact ranges vary by lab, higher percentages often suggest poorer blood sugar control, while lower percentages may indicate better management.

What might affect my results?

Several factors can influence HbA1c, including recent blood sugar fluctuations, pregnancy, certain medications (like insulin or blood pressure drugs), or conditions like anemia or kidney disease. Always discuss any concerns with your healthcare provider.

Reference range

Normal: 4.0-5.6%N/A

Specimen: whole-blood

Fasting for 8-12 hours required. Water is permitted. Avoid chewing gum and smoking before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: HbA1c is a critical tool for diagnosing diabetes, monitoring treatment effectiveness, and preventing long-term complications. It’s used alongside other tests to guide treatment plans, such as diet, exercise, or medication adjustments.

Short name

HbA1c

Frequently asked questions

How often should I get this test?
Your doctor will determine how frequently you need HbA1c testing based on your health status. Typically, people with diabetes check it every 3–6 months, while others may need it less often.
What if my results are outside the normal range?
If your HbA1c is higher than recommended, your doctor may adjust your treatment plan to improve blood sugar control. If it’s lower, they might reassess your needs or check for potential causes like overmedication.
Can lifestyle changes impact my HbA1c results?
Yes! Improving diet, increasing physical activity, and managing stress can help lower HbA1c levels over time. Small, consistent changes often lead to better long-term results.
  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