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Lab Dept:
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Urine/Stool
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Test Name:
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LEAD, TIMED URINE
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General Information
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Lab Order Codes:
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PBUR
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Synonyms:
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Pb, Urine Quantitative
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CPT Codes:
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83655 - Lead
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Test Includes:
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Urine Lead concentration reported in mcg/specimen.
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Logistics
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Test Indications:
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Useful for detecting lead toxicity.
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Lab Testing Sections:
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Urine/Stool - Sendouts
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Referred to:
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Mayo Medical Laboratories (MML Test# 8600)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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1 - 3 days, test set up Monday – Saturday
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Special Instructions:
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Submit an entire 24-hour urine collection. No preservative. Refrigerate specimen during and after collection.
Note: Starting and ending times of collection are required for a timed urine collection and must be documented electronically or on the proper request form.
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Specimen
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Specimen Type:
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Urine, timed collection
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Container:
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Plastic leakproof container (No preservative). Urine GUARD® collection container is preferred for a timed urine sample. A plastic urine container(s) with no metal caps or glued inserts.
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Draw Volume:
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Submit an entire 24-hour urine collection
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Processed Volume:
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10 mL from a 24-hour urine collection
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Collection:
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For timed urine collections, empty the bladder, discard the voided sample, and note the start time. Collect all urine voided for the specified time period. At the end of the period, note the finishing time, add the last voided sample to the container by emptying the bladder. Bring the refrigerated container to the lab. Make sure all specimens submitted to the laboratory are properly labeled with the patient’s name, medical record number and date of birth.
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Special Processing:
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Lab Staff: Measure and total urine volume. Mix collection well before aliquot is taken. Aliquot 10 mL urine to a clean, plastic container with no metal cap or glued insert. Record total volume and duration. Refrigerate within 4 hours of completion of 24-hour collection. Keep specimen refrigerated. Send refrigerated. Forward promptly.
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Patient Preparation:
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Gadolinium is known to interfere with most metals tests. If gadolinium-containing contrast media has been administered, a specimen cannot be collected for 96 hours.
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Sample Rejection:
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Mislabeled or unlabeled specimens
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Interpretive
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Reference Range:
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All ages:
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0 – 4 mcg/specimen
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The reference values are for a 24 hour collection.
Urinary excretion of <125 mcg of lead per 24 hours is not associated with any significant lead exposure. Urinary excretion >125 mcg of lead per 24 hours is usually associated with pallor, anemia, and other evidence of lead toxicity.
Increased urine lead excretion rate indicates significant lead exposure. Measurement of urine lead excretion rate before AND after chelation therapy has been used as an indicator of lead exposure. An increase in lead excretion rate in the post chelation specimen of up to 6 times the rate in the pre-chelation specimen is normal. Blood lead is the best clinical correlate of toxicity.
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Critical Values:
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N/A
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Limitations:
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This test is not a substitute for blood lead screening.
High concentrations of gadolinium and iodine are known to interfere with most metals tests. If either gadolinium or iodine containing contrast media has been administered, a specimen cannot be collected for more than 96 hours.
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Methodology:
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Inductively Coupled Plasma/Mass Spectrometry (ICP/MS)
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References:
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Mayo Medical Laboratories (January 2011)
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Updates:
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7/13/2010: Units change from ug/specimen to mcg/specimen.
1/5/2011: Reference range update.
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