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HelpOrder Code CALU Calcium, 24 Hour, Urine
Useful For
Evaluation of calcium oxalate and calcium phosphate kidney stone risk, and calculation of urinary supersaturation
Evaluation of bone diseases, including osteoporosis and osteomalacia
Special Instructions
Method Name
Photometric
Reporting Name
Calcium, 24 HR, USpecimen Type
UrineNecessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Patient Preparation: Patient cannot have a laxative during the 24-hour collection period.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: 24-hour graduated urine container with no metal cap or glued insert
Submission Container/Tube: Plastic, 5 mL tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 4 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. Refrigerate specimen within 4 hours of completion of 24-hour collection.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 30 days | ||
| Ambient | 72 hours |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitabilityReference Values
Males: <250 mg/24 hours*
Females: <200 mg/24 hours*
*Values represent clinical cutoffs above which studies have demonstrated increased risk of kidney stone formation. These values were not determined in a reference range study.
Reference values have not been established for patients who are younger than 18 years of age.
Reference values apply to 24-hour collection.
Method Description
Calcium ions react with 5-nitro-5'-methyl-BAPTA (NM-BAPTA) under alkaline conditions to form a complex. This complex reacts in the second step with EDTA. The change in absorbance is directly proportional to the calcium concentration and is measured photometrically.(Package insert: Roche CA2 kit. Roche Diagnostics; V5.0 03/2019)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82340
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Day(s) Performed
Monday through Sunday