Cyclic Adenosine Monophosphate (cAMP), Urinary Excretion, Serum and Urine
Use
This test is useful for the differential diagnosis of hypercalcemia and is particularly valuable as an adjunct to serum parathyroid hormone (PTH) measurements. It aids in identifying parathyroid hormone resistance states, such as pseudohypoparathyroidism, and in distinguishing between PTH and non-PTH mediated hypercalcemia. Elevated urinary cAMP measurements indicate hyperparathyroidism, occurring in about 85% of patients with the condition, and assist in diagnosing hypoparathyroid disorders.
Special Instructions
Both serum and urine specimens are required for this test. Serum should be collected at the same time as the urine specimen.
Limitations
Parathyroid suppression does not conclusively reduce urinary cAMP excretion to subnormal levels, which may influence the interpretation of conditions such as hypoparathyroidism. Additionally, cAMP levels might not significantly increase in cases of type I pseudohypoparathyroidism following PTH stimulation.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 21052-6
- 22712-4
- 2160-0
- 2161-8
Result Turnaround Time
2-11 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Preferred: Serum gel, Acceptable: Red top, Submission: Plastic vial
Collection Instructions
Within 2 hours of collection, centrifuge serum gel or red-top tubes and transfer the serum into a plastic vial. Label the specimen as serum.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 7 days (preferred), Refrigerated |
| Frozen | 90 days |