Lab Information Manual

Laboratory:

Clinical Biochemistry (AUTOMATED)

Test Name:

PHOSPHATE - (P)

Test Code: P

Clinical Information:

88% of the phosphorous contained in the body is localized in bone in the mineral form hydroxyapatite. The remainder is involved in carbohydrate metabolism or as a constituent of phospholipids, nucleic acids and ATP.

Phosphate determination is useful in the diagnosis and management of a variety of disorders including bone, parathyroid and renal disease. Phosphate levels alone are of limited diagnostic value and should be interpreted along with plasma calcium levels.

Common causes of hypophosphatemia are: shift of phosphate from extracellular to intracellular, renal phosphate wasting, loss from the gastrointestinal tract, and loss from intracellular stores.

Hyperphosphatemia occurs in CKD patients (stage ≥4) secondary to an inability of the kidneys to excrete phosphate. Other factors may relate to increased phosphate or vitamin D intake.

Patient preparation instructions: Fasting may be preferred as levels tend to fall post prandially.

Clinical Practice Change Reporting-Changes-to-Plasma-Creatinine-Urea-Urea-Creatinine-Ratio-Calcium-Phosphate-and-Parathyroid-Hormone-PTH-–-Reference-Intervals-Update 1-MAR-24

Collection Devices:

Preferred Device:	1 - Li Heparin Plasma Separator Tube(s) - Full Tube Collection Li Heparin Plasma Separator Tube(s) - Full Tube Collection Manufacturer: BD (Becton Dickinson) Catalogue #: 367962
Alternate Device:	1 - Serum Tube(s), with or without barrier gel - Full Tube Collection Serum Tube(s), with or without barrier gel - Full Tube Collection Manufacturer: Greiner or Becton Dickinson Catalogue #: Greiner: 057352 BD: 367988 or 366430

Pediatric samples should be collected in LiHep PST microtainer (0.6 mL)

Specimen Required:

Plasma: 2.0 mL

Pediatric Plasma: 0.2 mL

Specimen Stability:

Ambient: 24 hours

Refrigerated: 4 days

Frozen: 1 year at -20^oC

Referral:

Serum: 2.0 mL

Adult Volume: 2.0 mL serum or plasma aliquoted
Shipping & Storage: Samples must be transferred to an aliquot tube and stored/shipped

· Refrigerated if off-site testing to be performed within 24 hours of collection

· Frozen if testing to be performed after 24 hours

See #110-10-05 Serum / Plasma Separation Procedure & Transport

Requisition:

_SH Biochemistry Hematology Requisition (R250-10-92)

_SH Hospital Biochemistry Hematology Non Winnipeg Brandon (R250-10-91)

_SH Winnipeg Brandon Biochemistry Hematology Requisition (R250-10-94)

_SH Winnipeg Brandon Hospital Biochemistry Hematology Requisition (R250-10-93)

Reference Values:

Age	Male	Female
0 – 14 d	1.71 – 3.15 mmol/L
15d – 12 m	1.47 – 2.54 mmol/L
1 – 4 y	1.33 – 2.06 mmol/L
5 – 12 y	1.28 – 1.82 mmol/L
13 – 15 y	1.11 - 1.88 mmol/L	1.00 - 1.70 mmol/L
16 – 18 y	0.94 – 1.55 mmol/L
≥ 19 y	0.81 – 1.45 mmol/L

Effective March 11, 2024

Conversion factor: mmol/L x 3.1 = mg/dL

Method of Analysis: Endpoint photometric, Ammonium Molybdate

Availability:

Stat or Routine