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Lead/Creatinine Ratio, 24-Hour Urine

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

Measures lead relative to creatinine in a 24-hour urine collection to help evaluate urinary lead excretion and account for urine concentration.

Quick summary

["This test evaluates lead exposure by comparing urinary lead with creatinine over a 24-hour collection."]

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

Key facts at a glance

LOINC
52931-3
Short code
Lead/Creat 24h Ur-sRto
Synonyms
Lead/Creat 24h Ur-sRto
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test measures lead and creatinine in urine collected for 24 hours. The lead result is compared with creatinine, which helps account for variations in urine concentration.

Why might I need this test?

It may be ordered to evaluate possible exposure to lead from the workplace, environmental sources, contaminated products, or other sources. Urinary testing can help assess recent exposure, especially when blood lead testing is also being performed.

How is the test performed?

Urine is collected into a special container for a full 24-hour period. Record the collection start and finish times, save every sample during that period, and note any urine that was missed so the laboratory can assess collection adequacy.

How do I prepare for the test?

Follow the laboratory's collection instructions and ask your clinician whether your work or other exposures could affect the result. Continue normal daily activities unless instructed otherwise, and make sure the container is kept and stored as directed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated lead-to-creatinine ratio may indicate increased lead absorption or exposure. Results should be interpreted alongside the collection adequacy, urine output, kidney function, exposure history, and other relevant tests. A missed portion of the collection or unusually dilute urine can make the result less reliable.

Short name

24-Hour Urine Lead/Creatinine Ratio

Frequently asked questions

What does the urine lead/creatinine ratio show?
It shows the amount of urinary lead relative to creatinine, helping account for how concentrated the urine is. It is primarily used to help assess lead exposure.
How do I collect a 24-hour urine sample?
Collect all urine into the provided container for exactly 24 hours, beginning and ending at the times specified by the laboratory. Ask the laboratory what to do if a sample is missed or if the container needs refrigeration.
Does an elevated result mean I was definitely poisoned?
An elevated result suggests increased lead exposure or absorption, but it does not by itself establish a diagnosis or the severity of effects. Your clinician will interpret it with your history, symptoms, and other test results.
  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