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HelpTest Code HMU24 Heavy Metals Screen, with Reflex, 24 Hour, Urine
Specimen Required
1. For the 48-hour period prior to the start of collection, as well as during the collection, patient should not eat seafood.
2. High concentrations of gadolinium and iodine are known to potentially interfere with most inductively coupled plasma mass spectrometry-based 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 aliquot container with no metal cap or glued insert
Submission Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 6 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.
Useful For
Detecting arsenic, cadmium, mercury, and lead exposure and toxicity using 24-hour urine specimens
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ASHU | Arsenic, 24 Hr, U | Yes, (order ASU24) | Yes |
| CDHMU | Cadmium, 24 Hr, U | Yes, (order CDU) | Yes |
| HGHU | Mercury, 24 Hr, U | Yes, (order HGU) | Yes |
| PBHU | Lead, 24 Hr, U | Yes, (order PBU) | Yes |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SPASU | Arsenic Speciation, 24 Hr, U | Yes | No |
Testing Algorithm
If arsenic concentration is greater than or equal to 10 mcg/L, then speciation will be performed at an additional charge.
Special Instructions
Method Name
Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS)
Reporting Name
Heavy Metal Scrn w/Reflex, 24 Hr, USpecimen Type
UrineSpecimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Reference Values
ARSENIC:
0-17 years: Not established
≥18 years: <35 mcg/24 h
CADMIUM:
0-17 years: Not established
≥18 years: <0.7mcg/24 h
MERCURY:
0-17 years: Not established
≥18 years: <2 mcg/24 h
Toxic concentration: >50 mcg/24 h
The concentration at which toxicity is expressed is widely variable between patients.
50 mcg/24 h is the lowest concentration at which toxicity is usually apparent.
LEAD:
0-17 years: Not established
≥18 years: <2 mcg/24 h
Interpretation
Arsenic:
Mayo Clinic uses the American Conference of Governmental Industrial Hygienists biological exposure index (BEI) as the reference value. The BEI is the sum of all the toxic species (inorganic arsenic plus methylated arsenic metabolites).
Physiologically, arsenic exists in a number of toxic and nontoxic forms. The total arsenic concentration reflects all the arsenic present in the sample regardless of species (eg, inorganic vs. methylated vs. organic arsenic). The measurement of urinary total arsenic levels is generally accepted as the most reliable indicator of recent arsenic exposure. However, if the total urine arsenic concentration is elevated, arsenic speciation must be performed to identify if it is a toxic form (eg, inorganic and methylated arsenic forms) or a relatively nontoxic organic form (eg, arsenobetaine and arsenocholine).
The inorganic toxic forms of arsenic (eg, As[III] and As[V]) are found in the urine shortly after ingestion, whereas the less toxic methylated forms, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), are the species that predominate longer than 24 hours after ingestion. In general, urinary As(III) and As(V) concentrations peak in the urine at approximately 10 hours and return to normal 20 to 30 hours after ingestion. Urinary MMA and DMA concentrations normally peak at approximately 40 to 60 hours and return to baseline 6 to 20 days after ingestion.
After a seafood meal (seafood generally contains the nontoxic, organic form of arsenic, eg, arsenobetaine), the urine output of arsenic may increase to over 300 mcg/24 h, after which it will decline.
This test can determine if the patient has been exposed to above-average levels of arsenic. It cannot predict whether the arsenic levels in their body will affect their health.
Cadmium:
In chronic cadmium exposure, the kidneys are the primary target organ. Urine concentrations of cadmium can be useful to assess long-term exposure and determine cadmium body burden. Collection of urine over 24 hours minimizes fluctuations of observed cadmium concentrations in random urine samples.
Cadmium excretion above 3.0 mcg/g creatinine indicates significant exposure to cadmium. For occupational testing, OSHA cadmium standard is less than 3.0 mcg/g creatinine, and the BEI is 5 mcg/g creatinine.
Mercury:
Daily urine excretion of mercury above 50 mcg/day indicates significant exposure (per World Health Organization standard).
Lead:
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 Pb body burden or long-term exposure.(3,4)
Urinary lead concentration increases exponentially with blood lead and can exhibit relatively high intra-individual variability, even at similar blood lead concentrations.(5,6)
Day(s) Performed
Monday through Friday
Report Available
1 to 3 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
82175
82300
83825
83655
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HMU24 | Heavy Metal Scrn w/Reflex, 24 Hr, U | 94575-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8678 | Cadmium, 24 Hr, U | 5612-7 |
| 48539 | Arsenic, 24 Hr, U | 5587-1 |
| 92408 | Mercury, 24 Hr, U | 6693-6 |
| 92409 | Lead, 24 Hr, U | 5677-0 |
| TIME4 | Collection Duration | 13362-9 |
| 92215 | Total Arsenic Concentration | 21074-0 |
| VL16 | Total Volume | 3167-4 |
Clinical Reference
1. Snoj Tratniid J, Falnoga I, Mazej D, et al. Results of the first national human biomonitoring in Slovenia: Trace elements in men and lactating women, predictors of exposure and reference values. Int J Hyg Environ Health. 2019;222(3):563-582
2. Sherman LS, Blum JD, Franzblau A, Basu N. New insights into biomarkers of human mercury exposure using naturally occurring mercury stable isotopes. Environ Sci Technol. 2013;47(7):3403-3409
3. Sakai T: Biomarkers of lead exposure. Ind Health. 2000;38(2):127-142
4. Skerfving S. Biological monitoring of exposure to inorganic lead. In: Clarkson TW, Friberg L, Nordberg GF, Sager PR, eds. Biological Monitoring of Toxic Metals. Rochester Series on Environmental Toxicity. Springer; 1988:169-197
5. Gulson BL, Jameson CW, Mahaffey KR, et al. Relationships of lead in breast milk to lead in blood, urine, and diet of the infant and mother. Environ Health Perspect. 1998;106(10):667-674
6. Skerfving S, Ahlgren L, Christoffersson JO. Metabolism of inorganic lead in man. Nutr Res. 1985;Suppl 1:601-607
7. Fillol CC, Dor F, Labat L, et al. Urinary arsenic concentrations and speciation in residents living in an area with naturally contaminated soils. Sci Total Environ. 2010;408(5):1190-1191
8. Caldwell KL, Jones RL, Verdon CP, Jarrett JM, Caudill SP, Osterloh JD. Levels of urinary total and speciated arsenic in the US population: National Health and Nutrition Examination Survey 2003-2004. J Expo Sci Environ Epidemiol. 2009;19(1):59-68
9. Lee R, Middleton D, Caldwell K, et al. A review of events that expose children to elemental mercury in the United States. Environ Health Perspect. 2009;117(6):871-878
10. Kosnett MJ, Wedeen RP, Rotherberg SJ, et al. Recommendations for medical management of adult lead exposure. Environ Health Perspect. 2007;115(3):463-471
11. De Burbane C, Buchet JP, Leroyer A, et al. Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental exposure levels. Environ Health Perspect. 2006;114(4):584-590
12. Agency for Toxic Substances and Disease Registry. Toxicological profile for arsenic. US Department of Health and Human Services. 2007. www.atsdr.cdc.gov/ToxProfiles/tp2.pdf
13. Strathmann FG, Blum LM. Toxic elements. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 44
14. Keil DE, Berger-Ritchie J, McMillin GA. Testing for toxic elements: a focus on arsenic, cadmium, lead, and mercury. Lab Med, 2011:42(12):735–742. https://academic.oup.com/labmed/article/42/12/735/2504927
15. Navas-Acien A, Francesconi KA, Silbergeld EK, Guallar E. Seafood intake and urine concentrations of total arsenic, dimethylarsinate and arsenobetaine in the US population. Environ Res. 2011;111(1):110-118. doi:10.1016/j.envres.2010.10.009
16. Bernhoft RA. Mercury toxicity and treatment: a review of the literature. J Environ Public Health. 2012;2012:460508. doi:10.1155/2012/460508
17. Tchounwou PB, Yedjou CG, Udensi UK, et al. State of the science review of the health effects of inorganic arsenic: Perspectives for future research. Environ Toxicol. 2019;34(2):188-202. doi:10.1002/tox.22673