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Hemoglobin A1c (HbA1c) measured by high-performance liquid chromatography (HPLC)

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

This test measures the average level of blood sugar (glucose) over the past 2–3 months, reflecting how well your diabetes is controlled.

Quick summary

["HbA1c helps doctors assess long-term blood sugar management and adjust treatment plans."]

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

Key facts at a glance

LOINC
110832-3
Short code
HAV IgM Msmt Ser
Synonyms
HAV IgM Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 HbA1c Matters for Diabetes Management

HbA1c provides a snapshot of your blood sugar control over time, which standard blood glucose tests (like fingerstick readings) can’t show. It’s a key tool for doctors to determine if your diabetes treatment is working effectively.

How HbA1c Works

HbA1c forms when hemoglobin (the oxygen-carrying part of red blood cells) binds to glucose. As red blood cells live for about 3 months, this test averages your blood sugar levels during that time.

What HbA1c Results Mean

Results are typically reported as a percentage (e.g., 6.5% or higher may indicate diabetes). Lower percentages suggest better blood sugar control, while higher percentages may signal poor management or complications.

Common Causes of Abnormal Results

Factors like recent blood loss, severe illness, or certain medications can temporarily affect HbA1c levels. Chronic conditions (e.g., kidney disease) or pregnancy may also influence results.

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 abnormal result may indicate poor diabetes control, requiring adjustments to diet, exercise, or medication. It doesn’t diagnose diabetes alone but is used alongside other tests to guide treatment decisions.
How often should I get an HbA1c test?
Most people with diabetes should get an HbA1c test every 3–6 months to monitor progress. Your doctor may recommend more frequent testing if your blood sugar is unstable or if you’re adjusting treatments.
Can HbA1c be affected by diet or exercise?
Diet and exercise can influence HbA1c levels over time, but the test reflects average trends. Short-term changes (like a single meal) may not immediately affect the result, but long-term habits matter most.
  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