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Hemoglobin A1c (HbA1c) by Fluorescence Immunoassay (FIA) in Whole Blood

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

This test measures the percentage of hemoglobin that is coated with sugar, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["Helps track diabetes management and long-term blood sugar control."]

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

Key facts at a glance

LOINC
105772-8
Short code
Haem influ DNA Ct Bld Pos Qn NAA+probe
Synonyms
Haem influ DNA Ct Bld Pos Qn NAA+probe
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 This Test Measures

HbA1c reflects the amount of sugar (glucose) attached to hemoglobin in red blood cells. It’s a key indicator of how well your blood sugar has been controlled over time, especially useful for diagnosing diabetes or assessing treatment effectiveness.

Why It Matters for You

Regular HbA1c testing helps prevent complications like nerve damage, kidney disease, or heart disease by ensuring your blood sugar stays within healthy ranges.

How It’s Done

A small blood sample is taken from your arm, and the test measures hemoglobin’s sugar coating using a fluorescence-based method.

What to Expect Before or After

No special preparation is needed. After the test, you may feel slight discomfort from the needle, but it’s usually over quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: HbA1c is critical for diagnosing prediabetes, diabetes, and monitoring chronic conditions. Values above or below typical ranges may signal poor or improved control, prompting adjustments to diet, medication, or lifestyle.

Short name

HbA1c

Frequently asked questions

Why do I need this test?
Your doctor may recommend it if you have diabetes, prediabetes, or if you’re at risk for blood sugar-related complications. It’s also used to check how well treatments are working over time.
What do my results mean?
Results are usually reported as a percentage. A higher percentage may indicate higher average blood sugar levels, while lower values could suggest better control. Your doctor will interpret results in the context of your health and treatment plan.
Can I change my diet before this test?
No special diet is required, but avoid extreme changes (like very high or low sugar intake) for at least 2 weeks before testing if your doctor recommends it. Follow their guidance for best accuracy.
  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