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Test Code PHOS Phosphorus Inorganic LAB113

Performing Laboratory

UnityPoint The Finley Hospital

Test Method

Timed Endpoint Method; Roche cobas Pro

Performance

Testing is performed Monday through Sunday.

Routine: Typically completed within 4 hours after the specimen arrives at the testing site.

STAT: Typically completed within 30 minutes after the specimen arrives at the testing site.

Specimen Requirement

  1. Lithium heparin plasma (green) is the specimen of choice. 0.5mL
  2. Serum (red/gold) and EDTA plasma (purple) are also acceptable sample types.
  3. It is recommended that the serum be separated from contact with cells within 2 hours from time of collection.
  4. Phosphorus serum/plasma specimens are stable for 24 hours at 15-25ºC, 4 days at 2-8ºC, and 1 year at -20ºC. 

Useful For

Phosphorus occurs in blood in the form of inorganic phosphate and in organically bound phosphoric acid. The small amount of extracellular organic phosphorus is found almost exclusively in the form of phospholipids. The ratio of phosphate to calcium in the blood is approximately 6:10. An increase in the level of phosphorus causes a decrease in the calcium level. The mechanism is influenced by interactions between parathormone and vitamin D. Hypoparathyroidism, vitamin D intoxication and renal failure with decreased glomerular phosphate filtration give rise to hyperphosphatemia. Hypophosphatemia occurs in rickets, hyperparathyroidism and Fanconi's syndrome.

Reference Values

Adults (>18 years): 2.5-4.5 mg/dL

Age  Male  Female 
<1 month  3.9-6.9  4.3-7.7 
1 month - <1 year 3.5-6.6  3.7-6.5 
1 - 3 years 3.1-6.0  3.4-6.0 
4 - 6 years  3.3-5.6  3.2-5.5 
7 - 9 years 3.0-5.4  3.1-5.5 
10 - 12 years 3.2-5.7  3.3-5.3 
13 - 15 years 2.9-5.1  2.8-4.8 
16 - 18 years 2.7-4.9  2.5-4.8 

CPT Code Information

84100 Chemistry: Phosphorus inorganic (phosphate)

LOINC Code Information

2777-1 Phosphate [Mass/Volume] In Serum Or Plasma