Test Directory

Useful for the differential diagnosis of patients with water balance disorders, including diabetes insipidus in conjunction with osmolality and hydration status.

Specimen Type: Plasma

Collection Container: Lavender Top (EDTA)

Desired Specimen Volume: 2 mL

1. Collect a lavender top (EDTA) tube via venipuncture.

1. Separate plasma from cells.
2. Transfer 2 mL of plasma to a LabCorp PP transpak frozen purple tube.
3. Freeze immediately.
4. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

 No isotopes administered within 24 hours prior to venipuncture.

Transport to the laboratory frozen. 

• Recently administered isotopes
• Plasma specimen not received frozen

 See patient report.

The assessment of circulating ADH levels is challenging because it is released in a pulsatile pattern and is rapidly cleared from plasma. Measurement of ADH is further complicated by the high ex vivo instability of the peptide.

Mixed forms of diabetes insipidus (DI) can exist, and both central and peripheral DI may be incomplete, complicating the interpretation of results.

• Arginine Vasopressin, AVP
• Vasopressin