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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Phosphate

Test Code(s): PO4 / PHOS

CPT Code(s): 84100

Methodology: Phosphomolybdate, UV

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.

Specimen Requirements

Specimen: Blood

Collection Container: Preferred: Green cap with yellow ring (PST)
Also Acceptable: Green top, Red cap with yellow ring (SST), Red top

Collection Volume: Preferred: 1 mL
Pediatrics: 0.4 mL

Sample Analyzed: Plasma or serum

Volume Required: Preferred: 0.5 mL
Pediatrics: 0.2 mL

Specimen Processing: Centrifuge.  Redraw specimen if hemolysis is present.  If a complete barrier has not formed, transfer cell-free plasma/serum to plastic vial.  Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Whole blood specimens greater than 2 hours old when received by the laboratory are not acceptable.

Stability: Ambient: 24 hours
Refrigerated: PST - 48 hrs; if off cells or SST - 4 days


Reference Interval:
 Males:    Females:  
 Age  mg/dL  Age  mg/dL
 0-5 years  3.9-6.9  0-5 years  3.9-6.9
 6-10 years  3.9-5.5  6-10 years  4.1-5.7
 11-13 years  3.9-5.5  11-13 years  3.5-5.5
 14-16 years  3.3-5.4  14-16 years  3.1-5.5
 17-19 years  2.9-4.9  17-19 years  2.5-4.5
 20 years and up  2.5-4.5  20 years and up  2.5-4.5


Critical Calls: View

Additional Information:

Patients on mannitol may have falsely decreased phosphate levels.

Phosphorus, serum

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