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Hemoglobin A1c (HbA1c) with 24-Hour Temperature-Adjusted Index

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

This test measures your average blood sugar levels over the past 2–3 months, adjusted for recent body temperature changes. It helps doctors assess long-term diabetes control.

Quick summary

["HbA1c reflects your blood sugar trends over time, adjusted for temperature variations to improve accuracy."]

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

Key facts at a glance

LOINC
50989-3
Short code
Horowitz index temp adj BldA+IhG-Rto
Synonyms
Horowitz index temp adj BldA+IhG-Rto
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What This Test Measures

HbA1c measures the percentage of hemoglobin molecules coated with glucose (glycated hemoglobin), which reflects your average blood sugar levels over the past 2–3 months. This test is particularly useful for people with diabetes or prediabetes to track long-term glucose control. The temperature adjustment accounts for minor fluctuations in blood viscosity due to body temperature, improving the reliability of the result.

Why It Matters in Diabetes Management

Unlike daily blood sugar checks, HbA1c gives a broader picture of your glucose management. A higher HbA1c suggests poor control, while a lower value indicates better management. Adjustments for temperature help ensure the test reflects true metabolic status rather than temporary factors.

How It’s Performed

This test uses a small blood sample (usually from your finger) collected in a lab. The sample is processed to measure glycated hemoglobin levels, with an additional calculation to account for temperature variations. Results are compared to standard reference ranges to determine your average blood sugar trends.

Common Uses and Who Needs It

Doctors use this test to diagnose diabetes, monitor treatment progress, and adjust medications. It’s especially helpful for people with type 1 or type 2 diabetes, gestational diabetes, or those at high risk for diabetes. Regular HbA1c checks help prevent complications like nerve damage or heart disease.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

HbA1c Temp-Adjusted Index

Frequently asked questions

How often should I get this test?
Typically, adults with diabetes should get an HbA1c test every 3–6 months to track progress. Your doctor may recommend more frequent checks if your blood sugar is unstable or if you’re adjusting medications. Children and teens with diabetes may need more frequent testing, especially if they’re younger or have other health conditions.
What do my results mean?
Results are usually reported as a percentage (e.g., 6.5%). A value below 6.5% is generally considered good control, while 7.0% or higher may indicate poor management. Your doctor will interpret results in the context of your overall health and treatment plan. Temperature-adjusted indices are used to refine these estimates further.
Can I fast before this test?
No fasting is required for HbA1c testing. Unlike some other blood tests, this one measures long-term glucose levels regardless of when you last ate. However, always follow your doctor’s instructions for any additional preparations.
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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