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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 percentage of hemoglobin A1c in your blood, reflecting your average blood sugar levels over the past 2–3 months.

Quick summary

["HbA1c helps doctors 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
71877-5
Short code
Hgb A MFr.DF Bld HPLC
Synonyms
Hgb A MFr.DF Bld HPLC
Category
hematology
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
12
Ref high
17.5
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
hplc
CPT
85018
SNOMED
900000000000003004
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

Why This Test Matters

HbA1c is a key indicator of how well your body manages blood sugar over time. Unlike daily blood sugar checks, it provides a broader picture of your glucose control, helping prevent complications like nerve damage or kidney disease.

How It’s Done

A small blood sample is taken from your arm and analyzed using high-performance liquid chromatography (HPLC), a precise method that separates and measures hemoglobin variants, including A1c.

What It Measures

HbA1c represents the proportion of hemoglobin molecules that have been glycosylated (attached to sugar) due to high blood sugar. This reflects your average blood sugar levels over months, not just recent spikes.

What the Results Mean

Results are typically reported as a percentage (e.g., 5.5%–6.5% is considered normal for non-diabetics; higher values indicate poorer control). Your doctor will interpret results in the context of your health and treatment plan.

Reference range

Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A

Specimen: whole-blood

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c

Frequently asked questions

What causes HbA1c levels to change?
HbA1c levels rise with chronic high blood sugar (e.g., diabetes) and fall with improved control (e.g., diet, medication). Factors like pregnancy, anemia, or certain medications may also influence results.
How often should I get this test?
Your doctor may recommend HbA1c testing every 3–6 months if you have diabetes. For pre-diabetes or those at risk, testing may be less frequent (e.g., annually). Follow your healthcare provider’s schedule.
Can diet or exercise affect HbA1c results?
Yes! While HbA1c reflects long-term trends, short-term lifestyle changes (like diet or exercise) can influence recent blood sugar levels. However, it doesn’t show immediate effects—it’s a snapshot of your average over months.
  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