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Hemoglobin A1c (HbA1c) with 24-hour urine collection for creatinine clearance calculation

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

This test measures your average blood sugar levels over the past 2–3 months and estimates how well your kidneys filter blood, using a 24-hour urine sample.

Quick summary

["Helps track long-term blood sugar control and kidney function together."]

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

Key facts at a glance

LOINC
96647-3
Short code
HLA-DPB1 Donr Low res
Synonyms
HLA-DPB1 Donr Low res
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
low-resolution
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 This Test Matters for Blood Sugar Control

HbA1c reflects your blood sugar levels over time, giving doctors a clearer picture of how well your diabetes or prediabetes is managed. This test alone doesn’t measure kidney function, but combining it with creatinine clearance helps assess kidney health indirectly.

How the Test Works: Blood Sugar and Kidney Function Link

Your blood is tested for HbA1c, which binds to red blood cells and stays there for about 3 months. A 24-hour urine sample is used to estimate creatinine clearance, a measure of kidney function. Together, these results help evaluate both diabetes management and kidney health.

What to Expect Before the Test

For HbA1c: No special preparation is needed, but fasting isn’t required. For creatinine clearance: Collect all urine for a full 24-hour period (start and end times noted). Drink fluids as usual unless advised otherwise.

Common Causes of Abnormal Results

High HbA1c may indicate poor blood sugar control, while abnormal creatinine clearance could signal kidney issues. Other factors like recent blood transfusions, anemia, or severe illness may affect HbA1c results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Combining Blood Sugar and Kidney Health

Short name

HbA1c + CrCl

Frequently asked questions

Will fasting be required for this test?
No, fasting is not required for HbA1c. However, you’ll need to collect a full 24-hour urine sample, starting and ending at the same time each day.
How often should I get this test?
Typically, HbA1c is checked every 3–6 months for diabetes management. Creatinine clearance may be included in routine kidney function tests or when kidney health is a concern.
Can diet or exercise affect these results?
HbA1c reflects long-term blood sugar trends, so short-term diet or exercise changes won’t alter it immediately. However, diet and exercise can influence creatinine clearance indirectly by affecting kidney function and hydration status.
  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