Osmolality (Faeces)

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Testing Laboratory

Counties Manukau | Middlemore Hospital

Department

Refer to Testing Lab link

Delphic Registration Code (Alpha Code)

FNAK

Test Code (Numeric Code)

0316

Laboratory Handling

Phlebotomy

Only liquid faeces suitable

Separating

Middlemore will spin & use the supernatant for testing.

Sample Stability

24 hours

Turnaround Time

1 day

Specimen Type

  • Faecal

Specimen Requirements

Tube/Container Type:

Preferred
  • Faeces Container (White Lid)
Acceptable
  • Specimen Container

Paediatric Specimen Requirements

Tube/Container Type:

Preferred
  • Faeces Container (White Lid)
Acceptable
  • Specimen Container

Pre-testing Requirements

To assess the concentrating ability of the kidneys in renal disease, polyuria, polydipsia, diabetes insipidus, and the syndrome of inappropriate ADH secretion.
It should be measured in conjunction with the serum osmolality.
Water deprivation or water loading tests may be required.

Last updated: 13/11/2026