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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

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. 

Day(s) Test Set Up

Monday through Sunday



Test Classification and CPT Coding