Department

Biochemistry

Suitable Specimen Types

Plain Spot Urine
24 Hour Urine Plain

Plain Random or 24 hour urine collection

Sample Processing in Laboratory

Usual

Sample Preparation

Acidify urine in the Laboratory (24hr urine acidified by adding 400 uL of 3M HCL)

Turnaround Time

< 1 day if Mon-Fri

Sample Stability

Usual

Phosphate (Urine)

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

None

Notes

Please note, from 22/7/19 analysis performed using Abbott Alinity analyser. The test is awaiting UKAS accreditation.

Reference Range

15-50 mmol/24hr (Source: Pathology Harmony recommendations)

Specifications

EQA Scheme?: Yes
EQA Status: RIQAS