Tubular Reabsorption of Phosphorus, Random Urine and Serum

Clinical Use

Use

This test is useful for assessing renal reabsorption of phosphorus in various pathological conditions associated with hypophosphatemia, such as hypophosphatemic rickets, tumor-induced osteomalacia, and tumoral calcinosis. It also aids in adjusting phosphate replacement therapy in severe deficiency states and monitoring renal tubular recovery from acquired Fanconi syndrome. Additionally, the test evaluates the glomerular filtration of phosphorus, providing insights into the renal phosphate threshold and defect in phosphate reabsorption.

Special Instructions

Not provided.

Limitations

The test interpretation depends on the clinical situation and should be used in conjunction with serum phosphorus concentration. A reduced tubular reabsorption of phosphate in the presence of hypophosphatemia indicates a renal defect in phosphate reabsorption. Although direct measurements of parathyroid hormone have replaced much of the utility of TmP/GFR measurements, it remains useful for assessing renal reabsorption of phosphorus in various pathological conditions associated with hypophosphatemia.

Test Details

New York Approved

Methodology

Automated Analyzer (Clinical Chemistry)

Biomarkers

4 components

Creatinine, Serum • Clinical ChemistryCreatinine, Random Urine • Clinical ChemistryPhosphorus (Inorganic), Serum • Clinical ChemistryTubular Phosphate Reabsorption, Random • Clinical Chemistry