Cyclic AMP - urine

Last updated: Monday, 06, August, 2007

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Item Process
Specimen

30 minute timed urine collections before and after infusion of parathyroid hormone (PTH) or antidiuretic hormone (ADH) as appropriate.

Method

Immunoassay.

Reference Interval

15-25 nmol/L.

Application

The test is rarely indicated.

Pseudohypoparathyroidism can be divided into types I and II on the basis of the response of urine cyclic AMP to infusion of PTH.

Familial nephrogenic diabetes insipidus can be diagnosed by the response of urine cyclic AMP to ADH. Although cyclic AMP is increased in hyperparathyroidism, parathyroid hormone levels are used for definitive diagnosis.

Interpretation

Type I pseudohypoparathyroidism has a defect proximal to cyclic AMP production and so cyclic AMP does not increase when PTH is infused. Whereas type II, which has a defect distal to cyclic AMP production, shows a normal response to infused PTH.

In familial nephrogenic diabetes insipidus, cyclic AMP does not increase after infusion of ADH.

Reference

Scriver CR et al eds. The Molecular and Metabolic Bases of Inherited Disease. 7th ed. McGraw Hill 1995.