Preferred Sample Type

Phosphate (Urine)

Suitable Specimen Types

24 Hour Urine (Acid Collection)

Phosphate (Urine)

Sample Preparation

Urine time and volume should be recorded on the form

Turnaround Time

1 day

Sample Processing In Laboratory


Sample Stability


General Information

Urinary phosphate analysis is useful in the differential diagnosis of hypo and hyperphosphataemia.

Hypophosphataemia with a low urinary excretion (i.e. <3 mmol="" 24h="" of="" phosphate="" is="" most="" likely="" due="" to="" decreased="" intake="" increased="" cell="" uptake="" or="" loss="" from="" the="" gut="" a="" high="" urinary="" excretion="" i="" e="">3 mmol/24hr> is associated with renal loss and together with a high plasma calcium concentration can be attributed to primary hyperparathyroidism or malignancy. A high urinary excretion with a normal or low plasma calcium implies secondary hyperparathyroidism, vitamin D deficiency, Fanconi syndrome, hypomagnesaemia, diuretic therapy or oncogenic osteomalacia.

Hyperphosphataemia with a urinary excretion of <50 mmol="" 24h="" is="" suggestive="" of="" hypoparathyroidism="" whereas="" a="" level="">50 mmol/24h suggests increased intake, cell destruction or bone malignancy. Other causes of hyperphosphataemia (e.g. renal failure, vitamin D toxicity, DKA & lactic acidosis) may be exluded using plasma creatinine or calcium measurements.


Patient Preparation


Reference Range

15-50 mmol/24hr 

Source of Reference Range

Pathology Harmony recommendations


  • EQA Status: NEQAS
  • EQAS Scheme: Yes

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