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Hemoglobin A1c (HbA1c) with probe-based measurement

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

This test measures the average blood sugar levels over the past 2–3 months by checking the percentage of hemoglobin molecules bonded to 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
7904-6
Short code
HAV RNA Ser Ql NAA+probe
Synonyms
HAV RNA Ser Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

What Is HbA1c Used For?

HbA1c is primarily used to diagnose diabetes, assess how well blood sugar is controlled over time, and guide treatment plans. It provides a snapshot of your average glucose levels, which can help prevent complications like nerve damage or kidney disease.

How Is the Test Performed?

A small blood sample is taken from your arm, usually during a routine visit to your healthcare provider. The test measures the percentage of hemoglobin (the oxygen-carrying protein in red blood cells) that has attached to glucose.

What Does a High or Low HbA1c Mean?

A higher HbA1c percentage (typically above 6.5%) suggests poor blood sugar control and may indicate diabetes or prediabetes. A lower percentage (below 5.7%) may indicate consistently healthy blood sugar levels, but individual results depend on your health status and treatment.

How Often Should You Get Tested?

Healthcare providers often recommend HbA1c testing every 3–6 months for people with diabetes to monitor progress and adjust treatments. Others may test less frequently if their blood sugar is stable.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c (Blood Sugar Control)

Frequently asked questions

Why might my HbA1c test be done differently than usual?
This test uses a specialized probe method to measure HbA1c, which may differ from standard lab techniques. Your provider will explain how this affects your results and interpretation.
Can HbA1c be affected by recent blood sugar changes?
HbA1c reflects average blood sugar over months, so recent spikes or drops (like from illness or diet) won’t immediately change the result. However, acute changes may briefly alter red blood cell turnover, which could slightly impact the reading.
Does HbA1c test for type 1 or type 2 diabetes differently?
No, HbA1c itself doesn’t distinguish between type 1 or type 2 diabetes. It measures overall blood sugar control, so your provider will use clinical context (symptoms, family history, etc.) to determine the likely diagnosis.
  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