This test has replaced Anti Diuretic Hormone (ADH)

This test is not Medicare Rebateable.

Test cost: $50

This test must be approved by the Chemical Pathologist before sending.

Sample is sent to Northern Pathology

Samples are to be centrifuged, aliquoted and frozen at -20 degrees within 24 hours of collection. 

Samples to be sent frozen.

For the investigation of diabetes insipidus (DI) and primary polydipsia (PP) in patients with confimed polyuria (>40 mL/kg/d.*

A baseline Copeptin level >21.4 pmol/L is 100% sensitive and specific for nephrogenic diabetes insipidus.

A baseline Copeptin level <2.6 pmol/L with prior fluid deprivation (>8hr) will indicate complete central DI likely

A stimulated Copeptin**  >4.9 pmol/L PP likely and <4.9 pmol/L partial central DI likely (94.0% specificity and 94.4% sensitivity)

_{*Without concurrent diabetes mellitus, hypercalcemia, pregnancy, uncorrected thyroid or adrenal insufficieny, and heart failure; **at sodium levels >147mmol/L following water deprivation.}