Centralized Core Laboratory:Chemistry
24 hour urine collection
Cause for rejection:
Urine collected within 48 hours after administration of gadolinium (Gd) containing contrast media (may occur with MRI studies) and acid preserved samples are unacceptable.
Sent to reference lab; Days performed Tues, Fri
Inductively Coupled Plasma/Mass Spectrometry (ICP-MS)
10.0 mL (minimum 5.0 mL) aliquot from a well-mixed 24 hour urine collection in a clean plastic container. Instruct patient on 24 hour urine collection. To begin the urine collection, have the patient void. DISCARD THIS URINE SPECIMEN. This is best done with the first morning specimen. Note the time and record on the requisition. From then on collect all that is voided and place in container. If more than one container is needed, please mark the first as #1 of 2 and retain on the floor until the collection is complete. The final void should be made 24 hours after the first void described earlier. The specimen should be included with the collection. Sample must be refrigerated during collection. Submit specimen in two trace element free containers. Note total volume and collection interval.
ARUP studies indicate that refrigeration of urine alone, during and after collection, preserves specimens adequately, if tested within 14 days of collection.
Diet and nutritional supplements may introduce interfering substances. Patients should be encouraged to discontinue nutritional supplements, vitamins, minerals, nonessential over-the-counter medications (upon advice of their physician). High concentrations of iodine may interfere with elemental testing. Abstinence from iodine-containing medications or contrast agents for at least 1 month prior to collecting specimens is recommended.
OC Power Word:
Chromium, urine: 0.0-5.0 ug/L
Chromium, urine(24 hrs): 0.0-6.0 ug/d
Chromium per gram creatinine: No reference interval established