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Test Code LAB6507 Phosphorus, Urine, 24Hr

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Patient Preparation: None

Collection Container/Tube:

Preferred: Plain, Brown-orange 24 hour urine collecion container with preservative. Call lab at 314-454-4268 to get collection container with preservative (specimen may be collected without acid preservative if refrigerated during entire collection).

Specimen Collection Volume: Entire urine specimen collected over 24 hour time period

Submission Container/Tube: If specimen is coming from outside facility, mix well and measure total volume before making aliquot with a minimum of 1.0 mL of urine into a plastic, leak-proof, screw-capped tube for transport labeling with volume and duration times as well as if collected with preservative (or send entire 24-hr urine jug refrigerated).

Special Instructions: 

  1. Refrigerate specimen during collection
  2. Note collection start and stop dates and times on collection container
  3. Call lab at 314-454-4268 to obtain 24-hour collection jug if needed
  4. Follow instructions on "Urine Collection"

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 2 hours from receipt in performing lab

Reference Values

Reference Interval: 

<16 years: No reference intervals established                                    
≥ 16 years: 400-1300 mg/24H

Critical Value: None established

Methodology

Molybdate UV

Limitations

  • NA

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: 

  • PRE-COLLECTION: If floor wants collection container with preservative, add 5 mL of 6 mol/L HCl to collection jug and label jug as containing acid
  • POST-COLLECTION: Mix well and measure total volume collected. If specimen collected without acid preservative, make aliqout container with minimum of 1.0 mL urine . pH urine to <3 with 6NHCl. Then centrifuge the pH'd urine and removed cleared urine into a Roche-false bottom tube for testing. Label the aliquot with pH on label

Processed Volume: minimum 0.3 mL urine

Analyte Stability:

Specimen Type Temperature Time
urine (non-acidified)    Ambient or Refrigerated    4 hours non-acidified   
urine (acidified)        Ambient 2 days    
  Refrigerated     3 days     
  Frozen  6 monhts     

NOTE:

  1. Total volume of specimen collected and collection duration period is required. Note this information on the aliquot container label and into LIS system
  2. If floor calls for collection container with preservative, add 5 mL of 6 mol/L HCL to 24-hr jug and label container as containing acid.
  3. if collection duration is <18 hours or >30 hours cancel the 24Hr orderable and re-order test using the Timed orderable

Test Classification and CPT Code

84105

LOINC

Phosph UConc:   2778-9

Volume Ur:          19153-6

Period:                 13362-9

Last Reviewed

07/2025