Sign in →

Test ID CALU Calcium, 24 Hour, Urine

Useful For

Evaluation of calcium oxalate and calcium phosphate kidney stone risk, and calculation of urinary supersaturations

 

Evaluation of bone diseases, including osteoporosis and osteomalacia

Method Name

Photometric, NM-BAPTA Reaction

Reporting Name

Calcium, 24 Hr, U

Specimen Type

Urine

Collection Container/Tube: 24-hour graduated urine container with no metal cap or glued insert

Submission Container/Tube: Plastic, 5-mL tube (Supply T465) 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:

1. 24-Hour volume is required.

2. See Urine Preservatives in Special Instructions for multiple collections.

 

Urine Preservative Collection Options

Ambient

Yes

Refrigerated

Preferred

Frozen

Yes

6N HCl

Yes

50% Acetic Acid

Yes

Na2CO3

No

Toluene

Yes

6N HNO3

Yes

Boric Acid

Yes

Thymol

Yes

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Clinical 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

 

Reference values have not been established for patients <18 years and >83 years of age.

Reference values apply to 24-hour collection.

Cautions

No significant cautionary statements.

Day(s) Performed

Monday through Sunday; Continuously.

Report Available

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82340

NY State Approved

Conditional