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Hemoglobin A1c (HbA1c) with mass fraction measurement by high-performance liquid chromatography (HPLC)

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

This test measures the average level of your blood sugar over the past 2–3 months by examining the percentage of hemoglobin molecules linked 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
54069-0
Short code
Hgb Barts MFr DBS
Synonyms
Hgb Barts MFr DBS
Category
hematology
Sample
serum
Container
Red-top tube (SST)
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
CPT
85018
SNOMED
900000000000003004
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 Does This Test Measure?

HbA1c reflects your blood sugar levels over time because hemoglobin in your red blood cells carries glucose. As glucose attaches to hemoglobin, it forms HbA1c. The test quantifies this attachment to assess how well your body manages blood sugar consistently.

Why Is This Test Important?

Unlike daily blood sugar checks, HbA1c provides a broader picture of your glucose control, helping doctors identify trends and adjust treatments like diet or medication.

How Is This Test Performed?

A small blood sample is taken from your arm, usually via a needle. The sample is processed to separate hemoglobin and measure the percentage of HbA1c using HPLC, a precise method that separates and detects different hemoglobin forms.

What Are Common Results?

Results are reported as a percentage (e.g., 5.7%–6.4% may indicate prediabetes; 6.5% or higher suggests diabetes). Exact ranges may vary by lab, so discuss results with your healthcare provider.

Reference range

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

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c (Blood Sugar Control)

Frequently asked questions

How often should I expect this test?
Typically recommended every 3–6 months for people with diabetes to track progress and adjust treatment plans. Your doctor will determine frequency based on your health needs.
What factors could affect my HbA1c results?
Recent blood sugar spikes (e.g., from illness, stress, or poor diet) may temporarily raise HbA1c. Smoking, pregnancy, or certain medications can also influence results. Always report any recent changes to your doctor.
Can I prepare for this test?
No special preparation is needed, but avoid smoking or drinking alcohol 24 hours before the test. If you’re on insulin or diabetes medication, check with your doctor first, as timing may matter.
  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