Tubular Reabsorption of Phosphorus, Random Urine and Serum

Tubular Reabsorption of Phosphorus, Random Urine and Serum Print

Test Mnemonic

TRPHOS

CPT Codes

82565 - QTY (1)
82570 - QTY (1)
84100 - QTY (1)
84105 - QTY (1)

Aliases

Hypophosphatemia
Phosphate

Includes

Phosphorus (inorganic), serum
Tubular reabsorption of phosphate (TRP)
Maximum rate of tubular phosphate reabsorption to glomerular filtration rate (TmP/GFR) ratio
Creatinine, Serum
Creatinine, Random urine

Performing Laboratory

Mayo Clinic Dpt of Lab Med & Pathology

Specimen Requirements

Volume	Type	Container	Collect Temperature	Transport Temperature	Special Instructions
0.5 mL	Serum	No additive (Red)		Refrigerated	Fasting required. Both serum and urine are required. Separate serum from cells ASAP and transfer to standard aliquot tube. Label specimen as serum.
4 mL	Urine, random	Clean container		Refrigerated	Both serum and urine are required. Label specimen as urine.

Minimum Specimen Requirements

Volume	Type	Container	Collect Temperature	Transport Temperature	Special Instructions
0.5 mL					Serum
1 mL					Urine

Stability

Environmental Condition	Description
Frozen	Serum: 7 days; Urine: 14 days
Refrigerated	Serum: 7 days; Urine: 30 days
Ambient	Serum: Unacceptable; Urine: 7 days

Days Performed

Sun - Sat

Turnaround Time

1 - 2 days

Methodology

Name	Description
Calculation
Colorimetric Enzyme Assay
Photometric

Reference Range

Creatinine, Random, U
Sex	Age From	Age To	Type	Range	Range Unit
	18 Years	99 Years	Normal	16 - 326	mg/dL
				Reference values have not been established for patients who are less than 18 years of age
Creatinine, S
Sex	Age From	Age To	Type	Range	Range Unit
Male	Months	11 Months	Normal	0.17 - 0.42	mg/dL
Male	1 Years	5 Years	Normal	0.19 - 0.49	mg/dL
Male	6 Years	10 Years	Normal	0.26 - 0.61	mg/dL
Male	11 Years	14 Years	Normal	0.35 - 0.86	mg/dL
Male	15 Years	99 Years	Normal	0.74 - 1.35	mg/dL
Female	Months	11 Months	Normal	0.17 - 0.42	mg/dL
Female	1 Years	5 Years	Normal	0.19 - 0.49	mg/dL
Female	6 Years	10 Years	Normal	0.26 - 0.61	mg/dL
Female	11 Years	15 Years	Normal	0.35 - 0.86	mg/dL
Female	16 Years	99 Years	Normal	0.59 - 1.04	mg/dL
Phosphorus (Inorganic), S
Sex	Age From	Age To	Type	Range	Range Unit
Male	1 Years	4 Years	Normal	4.3 - 5.4	mg/dL
Male	5 Years	13 Years	Normal	3.7 - 5.4	mg/dL
Male	14 Years	15 Years	Normal	3.5 - 5.3	mg/dL
Male	16 Years	17 Years	Normal	3.1 - 4.7	mg/dL
Male	18 Years	99 Years	Normal	2.5 - 4.5	mg/dL
Female	1 Years	7 Years	Normal	4.3 - 5.4	mg/dL
Female	8 Years	13 Years	Normal	4.0 - 5.2	mg/dL
Female	14 Years	15 Years	Normal	3.5 - 4.9	mg/dL
Female	16 Years	17 Years	Normal	3.1 - 4.7	mg/dL
Female	18 Years	99 Years	Normal	2.5 - 4.5	mg/dL
				Reference values have not been established for patients that are <12 months of age.
Random TmP/GFR (Tubular Maximum Phosphorus Reabsorption/GFR)
Sex	Age From	Age To	Type	Range	Range Unit
			Normal	2.6 - 4.4	mg/dL
			Normal	0.80 - 1.35	mmol/L
TRP (Tubular Reabsorption of Phosphorus)
Sex	Age From	Age To	Type	Range	Range Unit
				>80% see Note
				Note: tubular reabsorption of phosphorus levels must be interpreted in light of the prevailing plasma phosphorus and glomerular filtration rate

Special Info

Fasting is required. Both serum and urine are required. Grossly hemolyzed specimens will be rejected. This test is New York state approved.

Clinical Info

This test is useful for assessing renal reabsorption of phosphorus in a variety of pathological conditions associated with hypophosphatemia including hypophosphatemic rickets, tumor-induced osteomalacia, and tumoral calcinosis. It is also useful for adjusting phosphate replacement therapy in severe deficiency states monitoring the renal tubular recovery from acquired Fanconi syndrome.