ARUP's Laboratory Test Directory

Arsenic, Urine with Reflex to Fractionated : 0025000

Mnemonic: ARS U

Methodology: Inductively Coupled Plasma/Mass Spectrometry/High Pressure Liquid Chromatography
Performed: Mon-Fri
Reported: 1-5 days
Specimen Required: Patient Prep:  Diet, medication, and nutritional supplements may introduce interfering substances.  Patients should be encouraged to discontinue nutritional supplements, vitamins, minerals, nonessential over-the-counter medications (upon the advice of their physician), and avoid shellfish and seafood for 48 to 72 hours.

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.
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Storage/Transport Temperature:  10 mL aliquot from a well-mixed collection at 2-8°C (Min: 5 mL). Submit specimen in two ARUP Trace Element-Free Transport Tubes (ARUP supply #43116).

Remarks:  Record total volume and collection time interval on transport tube and on test request form.

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 (preferred): 2 weeks; Frozen: 1 year
Reference Interval:

 
Test Number Components Reference Interval
 Arsenic, Urine0-35.0 µg/L (based on Biological Exposure Index)
 Arsenic, Urine (24-hour)0-50.0 µg/d
 Arsenic per gram of creatinineNo reference interval (µg/g crt)
0020734Arsenic, Fractionated, Urine  
 
Test Number Components Reference Interval
 As Organic Refer to test 0020741
 Arsenic Total Inorganic Refer to test 0020737
 Arsenic, Methylated Refer to test 0020740
 Creatinine (24-hour)  
 
Male Female
3-8 years: 140-700 mg/d
9-12 years: 300-1300 mg/d
13-17 years: 500-2300 mg/d
18-50 years: 1000-2500 mg/d
51-80 years: 800-2100 mg/d
81 years and older: 600-2000 mg/d 		3-8 years: 140-700 mg/d
9-12 years: 300-1300 mg/d
13-17 years: 400-1600 mg/d
18-50 years: 700-1600 mg/d
51-80 years: 500-1400 mg/d
81 years and older: 400-1300 mg/d

Interpretive Data: Specific toxic thresholds for arsenic are not well defined.  The ACGIH Biological Exposure Index is 35 µg/L for the sum of the inorganic and methylated forms of arsenic.  For specimens with a total arsenic concentration between 35-2000 µg/L, fractionation is performed to determine the proportion of organic, inorganic and methylated forms.  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 >30 µg/gCRT despite a total arsenic concentration <35 µg/L; the laboratory will perform this on request.

The organic forms of arsenic, most commonly arsenobetaine, are considered nontoxic and arise primarily from food.  Inorganic forms of arsenic [As(III) and As(V)] are most toxic.  Methylated forms (MMA and DMA) arise primarily from metabolism of inorganic forms but may also come from dietary sources and are of moderate toxic potential.  As this test does not detect all species of arsenic, it is expected that the sum of the organic, inorganic and methylated forms will not equal the total arsenic concentration.
CPT Code(s): 82175; if reflexed, add 82175 
Cross References: As, Urine
 
 

 

 

 
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