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Hemoglobin A1c (HbA1c) with Mass Fraction Measurement

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

This test measures the average blood sugar level over the past 2 to 3 months by checking the percentage of hemoglobin (red blood cell protein) that is coated with sugar.

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
62388-4
Short code
HbA1c MFr Bld JDS/JSCC
Synonyms
HbA1c MFr Bld JDS/JSCC
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
Method
jds-jscc
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

What Is HbA1c Used For?

HbA1c is primarily used to diagnose diabetes and monitor how well blood sugar levels are controlled over time. It provides a snapshot of your average glucose levels, which can help your healthcare provider adjust treatment plans, such as medication or diet, to keep your blood sugar within a healthy range.

How Is HbA1c Different from Daily Blood Sugar Checks?

Unlike daily blood sugar tests (like fingerstick glucose checks), HbA1c gives a broader picture of your blood sugar trends over months. It’s less affected by short-term fluctuations (like stress or meals) and is a reliable indicator of long-term management.

Why Might You Need This Test?

Your doctor may order an HbA1c test if you have symptoms of diabetes (like frequent urination, excessive thirst, or unexplained weight loss), if you have risk factors (like obesity, family history, or high blood pressure), or if you’re already managing diabetes to assess your progress.

How Is the HbA1c Test Performed?

A small blood sample is taken from your arm, usually by a phlebotomist. The test measures the percentage of hemoglobin molecules that have sugar attached, reflecting your average blood sugar over the past 2–3 months.

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.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test if I have diabetes?
If you have diabetes, your doctor may recommend HbA1c testing every 2–4 months to monitor progress and adjust treatments. Frequency depends on your overall health, treatment goals, and how well your blood sugar is controlled.
What does an HbA1c result of 6.5% or higher indicate?
An HbA1c result of 6.5% or higher is diagnostic for diabetes (based on the American Diabetes Association criteria). However, even if your result is below 6.5%, it may still indicate prediabetes or poor long-term control, depending on your other health factors.
Can lifestyle changes alone improve my HbA1c?
Yes! Lifestyle changes like eating a balanced diet, staying physically active, and managing stress can significantly improve HbA1c levels. Some people may also need medication to help control blood sugar, but diet and exercise are foundational for most people with diabetes.
  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