Hypertonic saline suppression test (DFT)

Test/Investigation

Hypertonic saline suppression test (DFT)

Site(s) or Laboratory offering Test/Investigation

NNUH (Biochemistry)

Indications

This test is used to investigate whether a patient has an arginine vasopressin (AVP)-related disorder (previously known as diabetes insipidus)

Comments/Precautions

The laboratory MUST be informed before commencing this test. Please refer to local trust guidelines for DFT protocols. Please ensure all timings are clearly labelled on every sample.

Storage conditions and sample stability between collection and transport to Lab

Bring unseparated SST (yellow top) samples promptly to laboratory to allow time for sample to clot before centrifugation.

Sample type

Serum (yellow top) samples required - bring to lab urgently for serum sodium monitoring throughout the test. Urine samples may also be sent. Refer to local DFT protocol for timings

Turnaround times (TAT) Urgent/Routine/GP or OPD

Please refer to the individual tests included in this dynamic function test for turn-around times.

If UKAS Accredited Test indicate at which site

Please refer to the individual tests included in this dynamic function test