Heavy Metal/Creatinine Ratio, with Reflex, Random, Urine
Use
Preferred screening test for detection of arsenic, cadmium, mercury, and lead in random urine specimens. Arsenic, lead, cadmium, and mercury are well-known toxins characterized by increased urinary excretion; measurement of these metals in urine provides reliable detection of recent exposure to these toxins. Total arsenic elevation triggers reflex speciation to differentiate toxic inorganic forms from relatively non-toxic organic species.
Special Instructions
Reflex testing (Arsenic Speciation, Random, U – SPAS) is performed if total arsenic concentration is ≥10 µg/L, at additional charge. Patient should avoid seafood for 48 hours prior to collection. If gadolinium- or iodine-containing contrast was administered, delay specimen collection for 96 hours. Supplies: clean, metal-free plastic urine container (no metal cap or glued insert); urine tubes (10 mL, T068). Random urine specimen collected and submitted as per Metals Analysis Specimen Collection and Transport protocol.
Limitations
Elevated total arsenic warrants speciation to determine whether exposure is to toxic inorganic forms. Urinary mercury correlation with clinical symptoms is poor, and seafood consumption may contribute to urinary mercury levels. Urinary lead reflects recent exposure and has high intra-individual variability. Interpretation of cadmium requires consideration of body burden and exposure history.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 29589-9
- 2161-8
- 13463-5
- 5586-3
- 13471-8
- 13465-0
- 13466-8
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
6 mL
Minimum Volume
3 mL
Container
Clean plastic urine container with no metal cap or glued insert; 10 mL urine tube (T068) or clean plastic aliquot container
Collection Instructions
Random urine specimen; avoid seafood for 48 h prior; delay 96 h after gadolinium/iodine contrast
Patient Preparation
Do not eat seafood for 48 hours; delay collection 96 hours after contrast media
Causes for Rejection
Specimens evaluated for suitability; metal contamination (e.g., metal caps) cause rejection
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 7 days |
| Frozen | 7 days |