Lead, 24 Hour, Urine
Use
Detecting clinically significant lead exposure in 24‑hour specimens. This test is not a substitute for blood lead screening. Measurements of urinary lead (Pb) levels have been used to assess lead exposure. However, urinary lead excretion mainly reflects recent exposure and shares limitations in assessing long‑term exposure or body burden owing to high intra‑individual variability. Urinary lead concentration increases exponentially with blood lead. Interpretation should account for these limitations. Useful context: American College of Medical Toxicology position on post‑chelator urinary metal testing.
Special Instructions
Patient must provide 24‑hour urine volume in milliliters. High concentrations of gadolinium or iodine contrast media may interfere with metals testing; if administered, specimen collection should be delayed for 96 hours. Collection instructions: collect urine for 24 hours; refrigerate specimen within 4 hours after completion; use clean plastic containers with no metal cap or glued insert. Supplies: Urine Tubes, 10 mL (T068). For multiple collections or preservatives, see Metals Analysis Specimen Collection and Transport and Urine Preservatives‑Collection and Transportation for 24‑Hour Urine Specimens.
Limitations
Urinary lead excretion reflects recent exposure and has high intra‑individual variability even at similar blood lead concentrations. It shares limitations with blood lead for assessing body burden; it is not suitable for long‑term exposure assessment. Post‑chelator urinary metal testing lacks scientific validation and may be harmful according to the ACMT.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 13362-9
- 3167-4
- 5677-0
- 5677-0
- 13362-9
- 3167-4
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
3 mL
Minimum Volume
1.5 mL
Container
Clean, plastic urine container with no metal cap or glued insert; submission container: plastic, 10‑mL urine tube or clean plastic aliquot container with no metal cap or glued insert
Collection Instructions
Collect urine for 24 hours; refrigerate specimen within 4 hours of completion; see Metals Analysis Specimen Collection and Transport
Patient Preparation
If gadolinium or iodine contrast administered, delay collection for 96 hours
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 28 days |
| Refrigerated | 28 days |
| Frozen | 28 days |