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Test Code PHOS Phosphorus, LAB113



Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements


Preferred: Green-top (heparin) tube-Hemolyzed specimen is not acceptable.

Acceptable: Gold-top serum gel tube or plain red-top tube

Specimen Volume: 0.1 mL of plasma or serum

Stability: Samples should be separated immediately or within 2 hours due to erythrocytes

               containing phosphate concentrations several times greater than those found in the

               serum.  Separated specimens should be analyzed immediately or kept at 2 – 8°C

               and analyzed within 7 days. For longer storage, samples may be frozen at -20°C for

               up to 6 months.


Reference Values

0-12 years: 4.0-7.0 mg/dL

≥12 years: 2.5-4.9 mg/dL

Critical value: <1.0 mg/dL

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding


Useful For

Measurements of inorganic phosphorus are used in the diagnosis and treatment of various disorders, including parathyroid gland and kidney diseases, and vitamin D imbalance.