Antidiuretic hormone

Keywords: ADH

Specimen:

5 mL blood in EDTA tube. The tube should be pre-cooled and delivered to the laboratory on melting ice, for immediate separation at 4°C and freezing.

Method:

Immunoassay.

Reference Interval:

Depends on plasma Osmolality and intravascular volume.

Application:

The test may be used, in conjunction with plasma Osmolality, to distinguish between central and nephrogenic Diabetes insipidus.

Interpretation:

Central diabetes insipidus is associated with low ADH levels, regardless of plasma Osmolality.

Nephrogenic Diabetes inspidus is associated with increasing levels of ADH as plasma Osmolality increases.

Preferably performed as part of Water deprivation test.

Reference:

Janicic N, Verbalis JG. Metab Clin North Am 2003; 32: 459-481.