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Hemoglobin A1c (HbA1c) with previous blood test comparison

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

This test measures your average blood sugar levels over the past 2–3 months by examining your red blood cells. It helps doctors track how well your diabetes is controlled.

Quick summary

["HbA1c helps monitor long-term blood sugar trends and adjust treatment plans."]

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

Key facts at a glance

LOINC
60431-4
Short code
Date previous bx
Synonyms
Date previous bx
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 HbA1c Measures

HbA1c reflects the percentage of hemoglobin molecules coated with glucose (glycated hemoglobin). It provides a snapshot of your blood sugar control over time, accounting for daily fluctuations that a single blood sugar test might miss.

How It’s Used in Your Care

This test is often compared to your previous HbA1c results to assess trends. A stable or improving HbA1c suggests better diabetes management, while a rising level may indicate the need for adjustments in medication, diet, or activity.

Why Previous Results Matter

By comparing current and past HbA1c levels, healthcare providers can identify patterns—such as steady improvement, decline, or stability—that inform long-term treatment strategies. This comparison helps avoid sudden changes in therapy based on short-term spikes.

What to Expect During the Test

A simple fingerstick blood sample is drawn to measure HbA1c. No special preparation is needed, but fasting isn’t required. Results are typically available within a few days and shared with your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HbA1c Comparison

Frequently asked questions

How often should I expect this test?
HbA1c is usually checked every 3–6 months for most people with diabetes. Your provider may adjust frequency based on your blood sugar goals, stability, or other health factors.
Can I eat or drink before this test?
No, you don’t need to fast for HbA1c. However, avoid sugary drinks or snacks if your provider specifies a fasting test for another purpose.
What do my results mean if they’re higher than usual?
A higher HbA1c suggests poor blood sugar control. Work with your provider to explore lifestyle changes, medication adjustments, or other strategies to improve your levels.
  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