Skip to content

Hemoglobin A1c (HbA1c) with High-Performance Liquid Chromatography (HPLC) Analysis

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. It’s a key tool for managing diabetes and prediabetes.

Quick summary

["HbA1c helps doctors track long-term blood sugar control with a simple blood test."]

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

Key facts at a glance

LOINC
19775-6
Short code
Relevant H&P Endscpy
Synonyms
Relevant H&P Endscpy
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
endoscopy
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 in Diabetes Care

HbA1c provides a snapshot of how well your blood sugar has been controlled over time, even if your recent blood sugar levels have been stable. Unlike daily blood glucose checks, it gives a broader picture of your metabolic health, helping prevent complications like nerve damage or kidney disease.

How the Test Works

Your blood sample is analyzed using high-performance liquid chromatography (HPLC), a precise method that separates hemoglobin types based on their sugar content. The test measures the proportion of hemoglobin A1c relative to total hemoglobin, expressed as a percentage.

What Normal Results Mean

While specific reference ranges vary by lab, HbA1c results are often interpreted in relation to diabetes guidelines. Lower percentages may indicate better blood sugar control, while higher percentages suggest poorer management and potential risks for complications.

Common Causes of Abnormal Results

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

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

How often should I get an HbA1c test?
Typically, people with diabetes are advised to test every 3–6 months, while those at high risk for prediabetes may need testing annually. Your doctor will tailor recommendations based on your health status and treatment plan.
Can HbA1c be affected by diet or supplements?
Dietary changes like reducing sugar intake or following a balanced meal plan can improve HbA1c levels over time. Some supplements (e.g., chromium or magnesium) may indirectly support blood sugar control, but they don’t directly measure HbA1c.
What if my HbA1c is higher than expected?
A higher HbA1c may signal poor blood sugar control. Your doctor will review your treatment plan, including diet, medication adjustments, or lifestyle changes, to help lower it. Follow-up tests will monitor progress until levels stabilize.
  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