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Hemoglobin A1c (HbA1c) with Mass Fraction Measurement

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

This test measures the average level of hemoglobin A1c in your blood over the past 2 to 3 months. It helps doctors assess how well your blood sugar has been controlled over time.

Quick summary

["HbA1c reflects your long-term blood sugar management and is key for diabetes care."]

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

Key facts at a glance

LOINC
4569-0
Short code
Hgb D MFr Bld
Synonyms
Hgb D MFr Bld
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85018
SNOMED
900000000000003004
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 HbA1c Measures

HbA1c represents the percentage of hemoglobin molecules that are attached to glucose. This attachment forms a stable compound called hemoglobin A1c. Over time, high blood sugar levels increase the likelihood of this attachment, allowing doctors to gauge average glucose levels from months prior.

Why It’s Used in Diabetes Management

HbA1c is a critical tool for diagnosing diabetes and monitoring treatment effectiveness. It provides a snapshot of blood sugar control that isn’t affected by short-term fluctuations, such as those from meals or stress.

How It’s Performed

This test involves drawing a small sample of blood from your arm. The sample is processed to measure the proportion of hemoglobin A1c relative to total hemoglobin. The result is expressed as a percentage.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours if your doctor requests a fasting sample. Wear comfortable clothing and bring any medications you’re currently taking.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

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 the typical range (often 4–6% for non-diabetics) suggests poor blood sugar control and may indicate diabetes or prediabetes. Lower-than-normal results may indicate naturally low glucose tolerance or rare conditions.
Can HbA1c be affected by other health conditions?
Yes, conditions like anemia, kidney disease, or certain medications (e.g., some blood thinners) can influence HbA1c levels. Your doctor may adjust interpretations based on your overall health.
How often should I get an HbA1c test?
Typically, adults with diabetes check HbA1c every 3–6 months. Your doctor may recommend more frequent testing if your blood sugar is unstable or if you’re adjusting treatments.
  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