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Phosphorus

Phosphate, PO4, Inorganic Phosphate

Test Codes

EPIC: LAB5099, Beaker: PHOS, Antrim: 17259

Department

Chemistry

Specimen Collection Criteria

FOR EC AND INPATIENT SAMPLE COLLECTION ONLY:

Preferred Sample: One Light Green (Mint)-top Plasma Separator Tube (PST). (Minimum Whole Blood: 4.0 mL) 

Acceptable Sample: One Gold-top SST (Minimum Whole Blood: 4.0 mL) 

Do NOT use Dark Green-top Lithium or Sodium Heparin tubes.

FOR PHYSICIAN OFFICE/OUTREACH SAMPLE COLLECTION:

COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL) 

Contact Laboratory for acceptability of other tube types.
See Minimum Pediatric Specimen Requirements for Microtainer^® collection.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

• Moderate to grossly hemolyzed specimens.
• Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers^® to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Royal Oak Automated Chemistry Laboratory 
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 4 hours.

Reference Range

Age related reference range:

Age	Range (mg/dL)
0-14 days	5.6 - 10.5
15 days - 1 year	4.8 - 8.4
1-4 years	4.3 - 6.8
5-12 years	4.1 - 5.9
13-15 years	3.2 - 6.2
16-18 years	2.9 - 5.0
19 years - Adult	2.3 - 4.4

Test Methodology

Spectrophotometry.

Interpretation

• Serum or plasma phosphorus may be elevated in a number of conditions including renal failure, hypoparathyroidism, milk-alkali syndrome, diabetic ketoacidosis, dehydration, acromegaly, bone metastases and following cardiac resuscitation. Increases may also be found after strenuous exercise and in hemolyzed samples (these would normally be rejected by the Laboratory).
• Decreased serum/plasma phosphorus occurs following ingestion of carbohydrates, IV administered glucose and during treatment of diabetic ketoacidosis (as phosphorus moves into cells). Low phosphorus levels are also seen with primary hyperparathyroidism, vitamin D deficiency, septicemia, renal tubular disorders, malabsorption, severe burns and in severely malnourished patients or patients receiving PO₄-free fluids on a long term basis.
• Problems associated with severe hypophosphatemia include respiratory failure, decreased cardiac function, increased incidence of sepsis and CNS signs/symptoms.

Clinical Utility

Measurement of inorganic phosphorus aids in the diagnosis and management of various disorders, including those involving the parathyroid gland, kidney, bone, and vitamin D metabolism.

CPT Codes

84100

Contacts

Last Updated

10/29/2023