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22936 TRP (Tubular Reabsorption of Phosphorus)

TRP (Tubular Reabsorption of Phosphorus)
Test Code: NEOTRP
Test Components
Tests performed include serum and urine phosphorus, serum and urine creatinine plus a calculation for percent tubular reabsorption of phosphorus.​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Yes​
Urine
AND
Plasma or Serum
Urine Container
 
Plasma Separator Tube (PST)
 Serum Separator Tube (SST) or Red Top (RTT)​
1-3 mL
 
0.5 mL
​
0.5 mL
 
0.3 mL
​		 ​
Collection Processing Instructions
Adults: Patients should be fasting for at least 8 hours. Water is permitted during this fasting period.
Draw fasting specimen and separate serum from the blood within 60 minutes of venipuncture for phosphorus and creatinine. Specimen must be free of particulate matter including fibrin. Avoid venous statis.
For urine collect a random urine specimen without preservatives after voiding the morning urine. 24 hours urine is also acceptable, record total volume of the urine. Acceptable preservatives include 7 g sulfamic acid, 6N HCL.
 
 
Newborns: Draw 0.2 mL serum (1 mL red microtainer) and 1 mL random urine with no preservatives. Serum phosphorus has circadian rhythm (highest in the morning and lowest in the evening) and also subject to seasonal variation (maximum level in May and June, and low in winter months).
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​Ambient ​2 hours
Refrigerate​ 4 days​
Plasma/​Serum ​Ambient ​8 hours
Refrigerate​ 2 days​
Frozen​ 2 months​
Rejection Criteria
​​Test cannot be performed unless both a blood and urine specimen are available.
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ 2-4 hours​ Phosphomolybdate Complex Endpoint Assay & Modified Jaffe Kinetic Fixed Assay/Beckman AU
Test Information
In adults, the test lacks sensitivity and will give normal results in 25% of patients with hyperparathyroidism. Renal insufficiency will invalidate the test, causing a falsely low result.​
Reference Range Information
Performing Location Reference Range
Marshfield​ % TRP: 82-95%
See individual listings for serum and urine phosphorus and creatinine results​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84105 ​ ​ ​  Phosphorus, urine​ ​
82570 ​ ​ ​ Creatinine, urine ​ ​
84100  ​ ​ ​ Phosphorus, serum​ ​
82565  ​ ​ ​ Creatinine, serum​ ​
Test Components
Tests performed include serum and urine phosphorus, serum and urine creatinine plus a calculation for percent tubular reabsorption of phosphorus.​
Ordering Applications
Ordering Application Description
​Centricity ​Neo-Natal TRP
​Cerner ​TRP (Tubular Reabsorp of Phos)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
Yes​
Urine
AND
Plasma or Serum
Urine Container
 
Plasma Separator Tube (PST)
 Serum Separator Tube (SST) or Red Top (RTT)​
1-3 mL
 
0.5 mL
​
0.5 mL
 
0.3 mL
​		 ​
Collection Processing
Adults: Patients should be fasting for at least 8 hours. Water is permitted during this fasting period.
Draw fasting specimen and separate serum from the blood within 60 minutes of venipuncture for phosphorus and creatinine. Specimen must be free of particulate matter including fibrin. Avoid venous statis.
For urine collect a random urine specimen without preservatives after voiding the morning urine. 24 hours urine is also acceptable, record total volume of the urine. Acceptable preservatives include 7 g sulfamic acid, 6N HCL.
 
 
Newborns: Draw 0.2 mL serum (1 mL red microtainer) and 1 mL random urine with no preservatives. Serum phosphorus has circadian rhythm (highest in the morning and lowest in the evening) and also subject to seasonal variation (maximum level in May and June, and low in winter months).
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​Ambient ​2 hours
Refrigerate​ 4 days​
Plasma/​Serum ​Ambient ​8 hours
Refrigerate​ 2 days​
Frozen​ 2 months​
Rejection Criteria
​​Test cannot be performed unless both a blood and urine specimen are available.
Test Components
Tests performed include serum and urine phosphorus, serum and urine creatinine plus a calculation for percent tubular reabsorption of phosphorus.​
Reference Range Information
Performing Location Reference Range
Marshfield​ % TRP: 82-95%
See individual listings for serum and urine phosphorus and creatinine results​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ 2-4 hours​ Phosphomolybdate Complex Endpoint Assay & Modified Jaffe Kinetic Fixed Assay/Beckman AU
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84105 ​ ​ ​  Phosphorus, urine​ ​
82570 ​ ​ ​ Creatinine, urine ​ ​
84100  ​ ​ ​ Phosphorus, serum​ ​
82565  ​ ​ ​ Creatinine, serum​ ​
For most current information refer to the Marshfield Laboratory online reference manual.