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HelpTest Code CALU Calcium, 24 Hour, Urine
Method Name
Photometric
Specimen 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 |
|---|---|---|
| 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 suitabilityClinical Information
Calcium is the fifth most common element in the body. It is a fundamental element necessary to form electrical gradients across membranes, an essential cofactor for many enzymes, and the main constituent in bone. Under normal physiologic conditions, the concentration of calcium in serum and in cells is tightly controlled. Calcium is excreted in both urine and feces. Ordinarily about 20% to 25% of dietary calcium is absorbed and 98% of filtered calcium is reabsorbed in the kidney. Traffic of calcium between the gastrointestinal tract, bone, and kidney is tightly controlled by a complex regulatory system that includes vitamin D and parathyroid hormone. Sufficient bioavailable calcium is essential for bone health. Excessive excretion of calcium in the urine is a common contributor to kidney stone risk.
Reference 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.
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