Lead, 24-Hour Urine
The total amount of lead passed in your urine over 24 hours. It is less common than blood lead and is used mostly for follow-up or workplace monitoring.
AI-verified against cited sources. Awaiting expert reviewLOINC 5677-0
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What it is
Your kidneys clear some of the lead in your body into urine. For this test you collect all of your urine for a full day, and the lab measures the total lead in it. The result is given as micrograms (µg) of lead per day. Blood lead is the standard test for lead exposure, and urine lead is used as a second look in certain situations.
Why it matters
Urine lead can add information when a clinician is looking at lead exposure, especially at work. It is affected by how complete the collection was and how well the kidneys are working, so it is read together with blood lead and your history rather than on its own.
If it’s high
A higher result means more lead passed in your urine that day. This often follows recent exposure, but a sample that picked up lead from a container or from skin can also read high. The number alone does not show how much lead is in your body or whether it is causing problems.
Common causes
- Recent exposure to lead at work, at home or through a hobby
- Contamination from a collection container or from skin
- Recent use of a chelating drug, which makes urine lead rise and cannot be compared with a normal range
What can help
- Ask your clinician whether a blood lead test should be done too
- Ask how to find and reduce possible sources of lead at home or work
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
For adults: up to 8.1 µg/24 h. Source: ARUP Laboratories, American College of Medical Toxicology (Journal of Medical Toxicology).
- Adults (this one applies)up to 8.1 µg/24 h
Sources: ARUP Laboratories, American College of Medical Toxicology (Journal of Medical Toxicology)
What can affect your result
- Recent exposure to lead
- Whether all urine was collected over the full 24 hours
- Kidney function and how much urine you make
- Contrast dye used for imaging in the past few days or weeks
- Supplements, vitamins and minerals
- Contamination from containers or skin
- Containers and tubes that are not certified trace-element-free can add lead, and lead on skin can contaminate a sample.
- Contrast dye used for imaging (iodinated or gadolinium-based) can interfere. ARUP rejects urine collected within 72 hours after contrast, and advises waiting at least 14 days if kidney function is impaired.
- Supplements, vitamins and minerals can interfere. ARUP asks that any change be made on a physician's advice, so check with your clinician before collection.
- An incomplete 24-hour collection makes the total look lower than it is.
- Urine collected after a chelating (provoking) drug has no valid reference range.
Collect every urine sample over a full 24 hours. The lab records the total volume and the hours collected. Shows how much lead the kidneys cleared over the collection day.
When to talk to a clinician
Talk with the clinician who ordered the test about any result above the lab's range. Get urgent care for severe belly pain, repeated vomiting, confusion, weakness or seizures. ARUP does not list a critical value for urine lead.
Questions you could ask
- Why was a 24-hour urine test chosen instead of a blood test?
- Do any of my supplements or recent imaging tests matter for this result?
- Should we also check a blood lead level?
- Could my collection or the container have affected this result?
- Where might lead be getting into my body, and how can we reduce it?
Questions people ask
Why is blood lead usually preferred over urine lead?
Blood lead is the standard test used for routine lead exposure checks and for health department follow-up. Urine lead depends on a complete collection and on kidney function, so it is used in selected situations.
What is a provoked or chelation-challenge urine test?
It is a urine collection after a drug that pulls metals out of the body. The American College of Medical Toxicology recommends against it, because the results can be misleading and the usual ranges are not meant for it.
How do I convert µg per day to µmol per day?
Multiply µg per day by 0.004826, so 8.1 µg/day is about 0.039 µmol/day. To go the other way, multiply µmol per day by 207.2.
Show the science and sources
Units
- 1 µg/24 h = 1 µg/24 h
- 1 µg/24 h = 0.004826 µmol/24 h
- 1 µg/24 h = 4.826 nmol/24 h
Open the Urine Lead (24h) unit converter
For clinicians and researchers
ARUP measures urine lead by ICP-MS in a 24-hour or random collection and reports it per 24 hours, per volume and per gram of creatinine, with intervals of 8.1 µg/d or lower, 5.0 µg/L or lower and 5.0 µg/g creatinine or lower. Urine lead mainly reflects recent excretion and is less standardized than blood lead for judging exposure, because it depends on collection completeness, kidney function and sample contamination. The American College of Medical Toxicology recommends against chelator-provoked (post-challenge) urine metal testing, since no valid reference range exists for it. ARUP's test requires trace-element-free transport tubes and rejects urine collected within 72 hours of iodinated or gadolinium-based contrast. A total per-day value needs a complete, accurately timed collection; if collection time or volume is off, a creatinine-corrected result may help interpretation.
LOINC 5677-0 (primary), 14809-8. Specimen: urine-24h.
Sources
- Lead, Urine (test 0025060), ARUP Laboratories
- ACMT Recommends Against Use of Post-Chelator Challenge Urinary Metal Testing, American College of Medical Toxicology (Journal of Medical Toxicology) (2017)
- Lead (element, PubChem), PubChem (National Library of Medicine)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.