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Hemoglobin A1c (HbA1c) with Quantitative Measurement

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

This test measures the average level of blood sugar (glucose) over the past 2–3 months by assessing how much hemoglobin in your red blood cells is coated with glucose.

Quick summary

Helps 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
64374-2
Short code
FULLTIMEREGISTEREDNURSESTAFFPOSITIONSFILLEDATENDOFPERIOD
Synonyms
—
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 This Test Matters for Your Health

HbA1c is a key indicator of how well your blood sugar has been managed over time. Unlike daily blood glucose checks, this test provides a snapshot of your average glucose levels, helping doctors adjust treatments like insulin or diet to improve long-term health.

How the Test Works

A small blood sample is taken from your arm, usually during a routine visit. The sample is analyzed to measure the percentage of hemoglobin molecules linked to glucose, reflecting your blood sugar trends over months.

What to Expect Before the Test

No special preparation is needed, but fasting is not required. If you’re unsure about your results, discuss them with your healthcare provider.

Common Causes of Abnormal Results

High HbA1c levels (above target) may indicate poor blood sugar control and could signal diabetes or prediabetes. Low levels (rarely seen) might suggest temporary factors like recent blood loss or severe anemia.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

HbA1c is essential for diagnosing diabetes (typically ≥6.5%), monitoring prediabetes (5.7%–6.4%), and guiding treatment plans. Regular monitoring helps prevent complications like nerve damage, kidney disease, or heart disease by keeping glucose levels stable.

Short name

HbA1c

Frequently asked questions

What does an abnormal HbA1c result mean?
An elevated HbA1c suggests your blood sugar has been consistently higher than recommended, which may require lifestyle changes or medication adjustments. A lower-than-normal result might indicate effective management, but always consult your doctor for interpretation.
Can HbA1c results change over time?
Yes, HbA1c levels can fluctuate based on diet, activity, medications, and underlying health conditions. Regular testing helps track trends and adjust care plans accordingly.
Is fasting required for this test?
No, fasting is not required. However, if you’re unsure about your results or have questions about timing, ask your healthcare provider for guidance.
  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