Hemoglobin A1c (HbA1c) with 24-hour fluid collection (HbA1c 24h)
This test measures the average level of hemoglobin A1c in your blood over the past 2–3 months, reflecting your blood sugar control during that time. A 24-hour fluid collection may be used to assess consistency or specific conditions requiring extended monitoring.
["HbA1c helps track long-term diabetes management by showing how well your blood sugar has been controlled over time."]
Key facts at a glance
- LOINC
- 104878-4
- Short code
- Hct 2h p Glc VFr Bld
- Synonyms
- Hct 2h p Glc VFr Bld
- Category
- glucose
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 36
- Ref high
- 50
- Critical range
- 18 N/A – 60 N/A
- Fasting
- true
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85014
- 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 Is This Test Done?
Doctors use HbA1c to diagnose diabetes, monitor treatment progress, and prevent complications like nerve damage or heart disease. It’s especially useful for people with type 1 or type 2 diabetes, prediabetes, or gestational diabetes.
How Is the Test Performed?
A blood sample is taken from a vein (usually in your arm). The test measures the percentage of hemoglobin molecules coated with sugar (HbA1c). If a 24-hour fluid collection is required, you may provide a continuous urine sample over 24 hours to assess consistency of results.
What Does the Result Mean?
Results are typically reported as a percentage. While exact ranges vary by lab, higher levels indicate poorer blood sugar control, while lower levels suggest better management. Your doctor will interpret results in the context of your overall health and treatment plan.
What Are the Risks?
The blood draw is generally safe but may cause mild discomfort or bruising. Rarely, there could be infection or excessive bleeding. If you have a bleeding disorder or are on blood thinners, discuss this with your doctor before the test.
Reference range
Adult males: 38-50%; Females: 36-44%N/A
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.
Clinical Significance: HbA1c is a gold-standard marker for long-term glucose control. Chronic elevations may signal undiagnosed diabetes, poor adherence to treatment, or metabolic disorders. It’s also used to guide insulin or medication adjustments and assess risk for diabetes-related complications.
Short name
HbA1c (24-hour)
Frequently asked questions
How often should I get this test?
What if my result is outside the normal range?
Can I eat or drink before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 17, 2026. · Read our editorial policy