ARUP's Laboratory Test Directory

Arsenic, Fractionated, Urine : 0020734

Mnemonic: AS UF

Methodology: Quantitative High Performance Liquid Chromatography/Quantitative Inductively Coupled Plasma-Mass Spectrometry
Performed: Mon, Fri
Reported: 1-5 days
Specimen Required: Collect: 24-hour or random urine collection. Specimen must be collected in a plastic container and should be refrigerated during collection. ARUP studies indicate that refrigeration of urine alone, during and after collection, preserves specimens adequately if tested within 14 days of collection.

Specimen Preparation: Transfer an 8 mL aliquot of urine from a well-mixed collection to ARUP Trace Element-Free Transport Tubes (ARUP supply #43116). Available online through eSupply using ARUP Connect™ or contact ARUP Client Services at (800) 522-2787. (Min: 2 mL) Record total volume and collection time interval on transport tube and on test request form.

Storage/Transport Temperature: Refrigerated. Also acceptable: Room temperature or frozen.

Unacceptable Conditions: Urine collected within 48 hours after administration of a gadolinium (Gd) containing contrast media (may occur with MRI studies). Acid preserved urine.

Stability (collection to initiation of testing): Ambient: 1 week; Refrigerated: 2 weeks; Frozen: 1 year
Reference Interval:
Test Number Components Reference Interval
As Organic By report
Arsenic Total Inorganic By report
Arsenic, Methylated By report

Interpretive Data: The ACGIH Biological Exposure Index for the sum of inorganic and methylated forms (species) of arsenic is 35 µg/L. For specimens with a total arsenic concentration between 35-2000 µg/L, fractionation is performed to determine the proportion of the inorganic, methylated, and organic forms. Inorganic forms of arsenic are most toxic. Methylated forms arise primarily from metabolism of inorganic forms but may also come from dietary sources and are of moderate toxic potential. The organic forms of arsenic are considered nontoxic and arise primarily from food. The sum of the inorganic, methylated, and organic forms of arsenic may be lower than the total arsenic level.

If low-level chronic poisoning is suspected, the µg/gCRT ratio may be more sensitive than the total arsenic concentration. It may be appropriate to fractionate specimens with a µg/gCRT ratio greater than 30 despite a total arsenic concentration less than 35 µg/L. Performed upon request.

See Compliance Statement B: www.aruplab.com/CS
CPT Code(s): 82175
Cross References: ASFR (Arsenic, Fractionated, Urine)