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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 blood sugar levels over the past 2–3 months by examining your red blood cells.

Quick summary

["HbA1c 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
72914-5
Short code
HNA 1c Ab Ser Ql IA
Synonyms
HNA 1c Ab Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 is HbA1c important?

HbA1c reflects your blood sugar levels over time, giving doctors a clearer picture of how well your diabetes is managed. Unlike daily blood sugar checks, it provides a snapshot of trends, helping prevent complications like nerve damage or kidney disease.

How is HbA1c tested?

A small blood sample is taken from your arm, usually via a fingerstick. The sample is processed using high-performance liquid chromatography (HPLC) to measure the percentage of hemoglobin bound to sugar.

What does an HbA1c result mean?

Results are typically reported as a percentage. A lower percentage (closer to 5.7%) suggests better blood sugar control, while higher percentages indicate poorer control. Exact values may vary by lab, so discuss your result with your healthcare provider.

What can affect HbA1c results?

Several factors can influence HbA1c, including recent blood sugar fluctuations, pregnancy, certain medications (like birth control), and conditions like anemia or kidney disease. Your doctor may adjust interpretations if these apply to you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: HbA1c is a key tool for diagnosing diabetes (typically ≥6.5%) and monitoring treatment. It helps identify trends in blood sugar control, reducing risks of long-term complications like heart disease, nerve damage, or vision problems.

Short name

HbA1c

Frequently asked questions

What does an HbA1c test tell me about my diabetes?
It shows your average blood sugar levels over the past 2–3 months, helping your doctor assess whether your current treatment plan is effective and make adjustments if needed.
Can HbA1c be affected by recent blood sugar spikes or dips?
Yes, extreme recent changes (e.g., severe illness, surgery, or recent medication changes) may temporarily alter HbA1c levels. Your doctor may request additional testing if results seem unusually high or low.
How often should I get an HbA1c test?
Typically every 3–6 months if you have diabetes, unless your doctor recommends more frequent testing (e.g., for rapid changes in treatment). Regular monitoring helps keep your blood sugar in target ranges.
  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