PHOSPHORUS, 24 HR URINE

Code
500.1250
Name
PHOSPHORUS, 24 HR URINE
Category
None
Department
Chemistry
Start Date
Expiration Date
Synonyms
PO4
CPT Codes
84105, 81050
Site
Main Lab
Reference Test
ATLAS Test Code

Specimen Information

Type

Urine, 24-Hour

Volume

5.0 ml

Transport Info

Refrigerated
6 month stability

Fasting Required?
False
Patient Instructions

Test should be completed within 2 hours of collection. Keep specimen on ice. If testing cannot be completed within 2 hours, acidify the specimen with 25ml 6N HCL.

Reference Range

340-1000 mg/24hr

Methodology

Colorimetric

Clinical Significance

Evaluate calcium/phosphorus balance. Evaluate nephrolithiasis.

Eighty eight percent of the phosphorus contained in the body is localized in bone in the form of calcium phosphate as the apatite Ca2+[Ca3(PO4)2]3 2-. The remainder is involved in intermediary carbohydrate metabolism and in physiologically important substances such as phospholipids, nucleic acids and ATP. Phosphorus occurs in blood in the form of inorganic phosphate and in organically bound phosphoric acid. The small amount of extracellular organic phosphorus is found almost exclusively in the form of phospholipids. The ratio of phosphate to calcium in the blood is approximately 6:10. An increase in the level of phosphorus causes a decrease in the calcium level. The mechanism is influenced by interactions between parathormone and vitamin D. Hypoparathyroidism, vitamin D intoxication and renal failure with decreased glomerular phosphate filtration give rise to hyperphosphatemia. Hypophosphatemia occurs in rickets, hyperparathyroidism and Fanconi’s syndrome.

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