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HelpTest Code ASUCR Arsenic/Creatinine, Ratio, with Reflex, Random, Urine
Specimen Required
Patient Preparation:
1. For the 48-hour period prior to start of collection, patient should not eat seafood.
2. 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 clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 6 mL
Collection Instructions:
1. Collect urine a random urine specimen.
2. See Metals Analysis Specimen Collection and Transport for complete instructions.
Useful For
Preferred screening test for detection of arsenic exposure using random urine specimens
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ASCU | Arsenic/Creatinine Ratio, U | No | Yes |
| CRETR | Creatinine, Random, U | No | Yes |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SPAS | Arsenic Speciation, Random, U | Yes | No |
Testing Algorithm
If total arsenic concentration is 10 mcg/L or greater, then speciation will be performed at an additional charge.
Special Instructions
Method Name
ASCU: Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (ICP-MS/MS)
CRETR: Enzymatic Colorimetric Assay
Reporting Name
Arsenic/Creat w/Reflex, Random,USpecimen Type
UrineSpecimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 72 hours |
Reference Values
ARSENIC/CREATININE:
0-17 years: Not established
≥18 years: <24 mcg/g creatinine
CREATININE:
≥18 years: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years of age.
Interpretation
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 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.
This test can determine if a patient has been exposed to above-average levels of arsenic. It cannot predict whether the arsenic levels in their body will affect their health.
Clinical Reference
1. 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. 20101;408(5):1190-1194
2. 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
3. Agency for Toxic Substances and Disease Registry: Toxicological profile for arsenic. US Department of Health and Human Services. August 2007. Available at www.atsdr.cdc.gov/ToxProfiles/tp2.pdf
4. 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
5. 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. doi:10.1309/LMYKGU05BEPE7IAW
6. 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
7. 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
Performing 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
82570
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ASUCR | Arsenic/Creat w/Reflex, Random,U | 13463-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CRETR | Creatinine, Random, U | 2161-8 |
| 608900 | Arsenic/Creatinine Ratio, U | 13463-5 |
| 608901 | Total Arsenic Concentration | 5586-3 |
Day(s) Performed
Monday through Friday