Lab Test

Calcium, Urine

Urine Calcium

Test Codes

24 Hour Urine: EPIC: LAB5439, CAU24, Random Urine: EPIC: LAB5438, CAU

Instructions

Note: 24 hour and random urine specimens MUST be collected separately. See below for collection criteria.

Specimen Collection Criteria

Collect: 24 hour urine or timed urine specimen with a 24 hour urine container with no preservatives.
Also acceptable: Random urine specimen in a screw-capped container (preferred) or another sterile collection cup. Preservatives are not acceptable for random urine specimens. (Minimum: 20 mL)

  • Refer to the table of Urine Preservative Options when multiple tests are requested.
  • Keep 24 hour urine specimen iced or refrigerated during collection.
  • Include start and end dates and times for the collection period on the specimen container.
Urine Preservative Options
No Preservative
6N Hydrochloric Acid
Boric Acid (10g)
Sodium Carbonate
50% Acetic Acid
Acceptable
PREFERRED
Acceptable
Unacceptable
Unacceptable

Physician Office/Draw Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire 24 hour urine collection, or random urine, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

  • Specimens not kept refrigerated (2-8°C or 36-46°F) during collection.
  • Specimens not collected and processed as indicated.

In-Lab Processing

Measure total volume of 24 hour urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot a minimum of 10 mL from the well-mixed 24 hour or time urine collection. The specimen must be acidified prior to analysis (see department procedure).

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): For longer storage.

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days (Royal Oak and Troy store an aliquot for 30 days.)

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory.

Grosse Pointe Chemistry Laboratory.
Royal Oak Automated Chemistry Laboratory.
Troy Chemistry Laboratory.

Performed

Sunday – Saturday.
Results available within 24 hours. 

Reference Range

Urine Calcium: 100-300 mg/24 hours.
Normal ranges for random urines or for collections other than 24 hours have not been established.

Test Methodology

Spectrophotometry.

Interpretation

  • Urine calcium may be increased due to hyperparathyroidism, osteoporosis, osteolytic bone metastases, vitamin D intoxication, Paget's disease, thyrotoxicosis, myeloma, malignant neoplasm of breast or bladder, osteitis deformans, and distal renal tubular acidosis.
  • Urine calcium may be decreased in hypoparathyroidism, pseudohypoparathyroidism, rickets, osteomalacia, malignant neoplasm in bone, celiac sprue disease, osteoblastic metastases, and steatorrhea.

Clinical Utility

24 hour urine calcium reflects intake, rates of intestinal calcium absorption, bone resorption and renal loss. Those processes relate to parathyroid hormone and vitamin D levels. Urinary calcium measurements are most useful for evaluation of patients with renal stones or a possible diagnosis of familial hypocalciuric hypercalcemia.

CPT Codes

82340
LOINC: 18488-7, 6874-2

Contacts

Last Updated

7/28/2021

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