Calcium/Creatinine, 24 Hour, Urine
Method Description Describes how the test is performed and provides a method-specific reference
Calcium concentrations in urine can be determined by inductively coupled plasma optical emission spectrometry. Aqueous acidic calibrating standards, quality control samples, patient specimens, and blanks are diluted with diluent containing an internal standard. In turn, all diluted blanks, calibrating standards, quality control samples, and patient specimens are aspirated into a pneumatic nebulizer and the resulting aerosol directed to the hot plasma discharge by a flow of argon. In the annular plasma the aerosol is vaporized, atomized, and then ionized. Emission signals from calcium and the internal standard are observed radially by the emission spectrometer. Instrumentation response is defined by the linear relationship of analyte concentrations versus the ratio of the calcium emission signals ratioed with the internal standard. After reagent blank subtraction, unknown sample calcium concentrations are calculated by entering the net unknown intensity ratios into the linear calibration equation.(Nixon DE, Moyer TP, Johnson P, et al: Routine measurement of calcium, magnesium, copper, zinc, and iron in urine and serum by inductively coupled plasma emission spectroscopy. Clin Chem 1986;32:1660-1665)
The enzymatic method for creatinine is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Roche Diagnostics, Indianapolis IN, 2004)
Supplemental Report Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 11 a.m.-6 p.m.