Sep 16, 2015




Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Chemistry


Phosphate (PHOS) Chemistry Lab Test

Name: Phosphate

Test Name: Phosphate

Health Link Test Code: PHOS

LIS Test Code: PO4

CPT Code(s): 84100

Methodology: Phosphomolybdate, UV

Days Performed: Daily, 24 hours.

In-Lab Turnaround Time: 4 hours.

Stat In-Lab Turnaround Time: 1 hour.

Specimen: Blood

Collection Container: Green cap with yellow ring (PST)

Also Acceptable: Green top, Red cap with yellow ring (SST), Red top

Collection Volume: 1 mL

Pediatric Collection Volume: 0.4 mL

Stability Ambient:

24 hours

Stability Refridgerated:

4 days

Stability Frozen:

1 year

Sample Analyzed: Plasma or serum

Testing Volume: 0.5 mL

Pediatric Testing Volume: 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 Hospital Laboratory. Transport with coolant pack if coming from clinic location.

Unacceptable Criteria:

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


Age mg/dL
0-14 days 5.6-10.5
15 days-11 months 4.6-8.4
1-5 years 4.3-6.8
6-12 years 4.0-5.9
13-16 years 3.4-6.2
17-18 years 3.1-5.0
19 years and up 2.3-4.7


Interpretation Type: Reference Interval

Critical Calls: yes

Additional Information:

Patients on mannitol may have falsely decreased phosphate levels.