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HelpTest Code PBU; SQ: LD24U Lead, 24 Hour, Urine
Reporting Name
Lead, 24 Hr, UUseful For
Detecting clinically significant lead exposure in 24-hour specimens
This test is not a substitute for blood lead screening.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering Guidance
The Centers for Disease Control and Prevention recommends venous blood collection for lead testing; see PBDV / Lead, Venous, with Demographics, Blood
Necessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Patient Preparation: High concentrations of gadolinium and iodine are known to interfere with most metal tests. If either gadolinium- or iodine-containing contrast media has been administered, a specimen should not be collected for 96 hours.
Supplies: Urine Tubes, 10 mL (T068)
Collection Container/Tube: Clean, plastic urine container with no metal cap or glued insert
Submission Container/Tube: Plastic, 10-mL urine tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 3 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. Refrigerate specimen within 4 hours of completion of 24-hour collection.
3. See Metals Analysis Specimen Collection and Transport for complete instructions.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
1.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Ambient | 28 days | ||
| Frozen | 28 days |
Special Instructions
Reference Values
0-17 years: Not established
≥18 years: <2 mcg/24 h
Day(s) Performed
Monday through Friday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83655
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PBU | Lead, 24 Hr, U | 5677-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 31085 | Lead, 24 Hr, U | 5677-0 |
| TM83 | Collection Duration | 13362-9 |
| VL84 | Urine Volume | 3167-4 |
Clinical Information
Increased urine lead excretion rate indicates significant lead exposure. Measurement of urine lead excretion rate before and after chelation therapy has been used as an indicator of lead exposure. However, the American College of Medical Toxicology (ACMT 2010) position statement on post-chelator challenge urinary metal testing states that "post-challenge urinary metal testing has not been scientifically validated, has no demonstrated benefit, and may be harmful when applied in the assessment and treatment of patients in whom there is concern for metal poisoning."
For more information see PBDV/ Lead, Venous, with Demographics, Blood.
Interpretation
Measurements of urinary lead (Pb) levels have been used to assess lead exposure. However, like lead blood, urinary lead excretion mainly reflects recent exposure and thus shares many of the same limitations for assessing lead body burden or long-term exposure.(1,2)
Urinary lead concentration increases exponentially with blood lead and can exhibit relatively high intra-individual variability, even at similar blood lead concentrations.(3,4)
Method Description
The metal of interest is analyzed by inductively coupled plasma mass spectrometry.(Unpublished Mayo method).
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS)