Test
Name

Calcium,
24-hour Urine

Test
Codes

262

Unit

mg/24h

Station

Chemistry

Synonym
Name/Abbreviation

Ca,
urine

CPT
Code

82340

Performing
Facility

American
Medical Labs, Herzliya Pituah

Analyzer

Roche cobas 6000

Test
Method

Colorimetric
assay

AML preferred
tube/ container

 24 Hour urine collection: suitable
plastic  container with at
least 10 mL 6N HCl (hydrochloric acid).

Storage
Instructions

Refrigerated

Stability:

48h 15-25
^oC

 4 days 2-8 ^oC

 3 weeks -15to -25 ^oC

Min.
Volume

10 mL of well
mixed urine from measured 24 hour collection.

Comments

Urinary
calcium reflects in part the relation between GFR and tubular
reabsorption.

Turn-Around-Time

One day

Intended
Use

Urine calcium
determinations are used to investigate effects of vitamin D, and
parathyroid hormone. The results reflect intake, rates of intestinal
calcium absorption, bone resorption and renal loss.

Limitations

Decreased in
patients on oral contraceptives. Lacks specificity for hyperparathyroidism
(HPT) when increased. Five percent of the population have hypercalciuria.

Measuring
range: 0.8-30.1 mg/dL

Patient
Preparation

 24 hour collection: the patient
will be instructed to void at 8 AM and discard the specimen. Then collect
all urines including the final specimen voided at the end of the 24-hour
collection period (i.e. 8 AM the next morning). Date and time of starting
colection and total volume must be stated. Screw the lid on securely.

Transport the
specimen promptly to the laboratory.

Reasons for
Rejection

Improper
labeling or sample collection.

Adult
Reference Ranges

 100-321 mg/24h