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HelpTest ID AVP Arginine Vasopressin, Plasma
Useful For
Diagnosis and characterization of diabetes insipidus
Diagnosis of psychogenic water intoxication
As an adjunct in the diagnosis of syndrome of inappropriate secretion of antidiuretic hormone secretion (SIADH), including ectopic arginine vasopressin production
Method Name
Radioimmunoassay (RIA)
Reporting Name
Arginine Vasopressin, PSpecimen Type
Plasma EDTASpecimen Type: Platelet-poor plasma
Collection Container/Tube: Lavender top (EDTA) iced tube
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions:
1. Have patient fast and thirst for 6 hours (no liquids, including water, are allowed).
2. Process 5 mL of EDTA whole blood as follows:
a. Spin down in a refrigerated centrifuge at approximately 1,000 x G (2,000 rpm for a 20-cm radius centrifuge) for 10 minutes.
b. Remove plasma, carefully avoiding the platelet/buffy coat.
Additional Information: This test should not be requested on patients who have recently received radioactive material.
Specimen Minimum Volume
1.15 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma EDTA | Frozen (preferred) | 14 days |
| Refrigerated | 24 hours |
Clinical Information
Arginine vasopressin (AVP), also known as antidiuretic hormone (ADH), is a hypothalamic polypeptide that is transported along the axons of the synthesizing neurons into the posterior pituitary gland. From there it is released into the systemic circulation after appropriate stimuli. The main regulators of AVP secretion are osmotic stimuli, provided by osmoreceptors located in the anteromedial hypothalamus, and volume stimuli, provided by receptors in neck vessels and heart. Under physiological conditions, volume stimuli always override osmotic stimuli.
The absence or presence of AVP is the major physiologic determinant of urinary free water excretion or retention. AVP acts principally on renal collecting tubules to increase water reabsorption. The antidiuretic effects of AVP are mediated by V2 vasopressin receptors. AVP can also increase vascular resistance through stimulation of V1 receptors.
Diabetes insipidus (DI) is characterized by the inability to appropriately concentrate urine in response to volume and osmol stimuli. The main causes for DI are decreased AVP production (central DI) or decreased renal response to AVP (nephrogenic DI).
AVP can also be secreted inappropriately in certain situations, particularly in elderly patients, leading to water retention and dilutional hyponatremia. Inappropriate AVP secretion might be observed with central nervous system pathology, such as head injury, stroke, or cerebral tumor, or as a side effect of central acting drugs that interfere with the hypothalamic regulation or AVP. Noncentral causes of inappropriate AVP secretion include peripheral stimuli that mimic central vascular hypovolemia, in particular severe low-output cardiac failure, and ectopic AVP secretion (usually by a bronchogenic carcinoma).
Reference Values
Adults: <1.7 pg/mL
Reference values were determined on platelet-poor EDTA plasma from individuals fasting no longer than overnight.
Cautions
Reference values were determined on platelet-poor EDTA plasma from individuals fasting no longer than overnight. A significant amount of circulating arginine vasopressin (AVP) is associated with platelets. Therefore, various conditions affecting platelets may also affect AVP levels. Platelet-rich specimens have been shown to have AVP levels on the order of 10 times the value of platelet-poor specimens.
AVP levels obtained in the process of a water deprivation test can be difficult to interpret because of the many non standardized variables in this test. Expert consultation is recommended in these circumstances.
This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive samples received in the laboratory will be held and assayed after the radioactivity has sufficiently decayed. This will result in a test delay.
Day(s) Performed
Wednesday; 1 p.m.
Report Available
3 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
84588