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HelpTest Code CARU Cyclic Adenosine Monophosphate (cAMP), Urinary Excretion, Serum and Urine
Specimen Required
Both serum and urine are required. Serum must be collected at the time of the urine collection.
Specimen Type: Serum
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Within 2 hours of collection serum gel tubes should be centrifuged.
2. Within 2 hours of collection red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial.
3. Label specimen as serum.
Specimen Type: Urine
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube: Plastic vial
Specimen Volume: 5 mL
Collection Instructions:
1. Collect a random urine specimen.
2. Label specimen as urine.
Useful For
Differential diagnosis of hypercalcemia
As an adjunct to serum parathyroid hormone measurements, especially in the diagnosis of parathyroid hormone resistance states, such as pseudohypoparathyroidism
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ACREA | Creatinine, S | Yes, (order CRTS1) | Yes |
| CAMP | Cyclic Amp, Urinary Excretion | No | Yes |
| CRETR | Creatinine, Random, U | Yes, (order RCTUR) | Yes |
Method Name
ACREA, CRETR: Enzymatic Colorimetric Assay
CAMP: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Cyclic Amp, Urinary ExcretionSpecimen Type
SerumUrine
Specimen Minimum Volume
Serum: 0.5 mL
Urine: 1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | 90 days | |
| Urine | Refrigerated (preferred) | 28 days |
| Frozen | 28 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
3'-5'-cyclic adenosine monophosphate (cAMP) functions as an intracellular "second messenger" playing a key role in cellular functions such as transcription, metabolism, mitochondrial homeostasis, cell division, and cell death. Several hormones such as calcitonin, dopamine, glucagon, glucagon like peptide-1, vasoactive intestinal peptide and parathyroid hormone (PTH) have been shown to increase the formation of cAMP in the kidney by the action of adenylate cyclase. It has been shown that a significant portion of the urinary cAMP is generated in response to parathyroid hormone. As a result, urinary cAMP measurements can be used for distinguishing between PTH or non-PTH mediated hypercalcemia and aid in the differential diagnosis of hypercalcemia. Additionally, measurements of urinary cAMP levels following PTH stimulation are useful for the differential diagnosis of hypoparathyroid disorders. Urinary cAMP is elevated in about 85% of patients with hyperparathyroidism.
Reference Values
CYCLIC AMP
1.3-3.7 nmol/dL of glomerular filtrate
CREATININE, SERUM
Males
0-11 months: 0.17-0.42 mg/dL
1-5 years: 0.19-0.49 mg/dL
6-10 years: 0.26-0.61 mg/dL
11-14 years: 0.35-0.86 mg/dL
≥15 years: 0.74-1.35 mg/dL
Females
0-11 months: 0.17-0.42 mg/dL
1-5 years: 0.19-0.49 mg/dL
6-10 years: 0.26-0.61 mg/dL
11-15 years: 0.35-0.86 mg/dL
≥16 years: 0.59-1.04 mg/dL
CREATININE, URINE
No reference values apply. Interpret with other clinical data.
Interpretation
3'-5' -cyclic adenosine monophosphate (cAMP) is elevated in about 85% of patients with hyperparathyroidism and in about 50% of patients with humoral hypercalcemia of malignancy.
Minimal to no increase in cAMP levels following parathyroid hormone stimulation suggests type I pseudohypoparathyroidism.
Cautions
Parathyroid suppression (hypoparathyroidism) does not lower urinary 3'-5'-cyclic adenosine monophosphate (cAMP) excretion to definitively subnormal values.
Clinical Reference
1. Shaw JW, Oldham SB, Rosoff L, Bethune JE, Fichman MP. Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia. J Clin Invest. 1977;59(1):14-21. doi:10.1172/JCI108611
2. Babka JC, Bower RH, Sode J. Nephrogenous cyclic AMP levels in primary hyperparathyroidism. Arch Intern Med. 1976;136(10):1140-1144
3. Dohan PH, Yamashita K, Larsen PR, Davis B, Deftos L, Field JB. Evaluation of urinary cyclic 3'5'-adenosine monophosphate excretion in the differential diagnosis of hypercalcemia. J Clin Endocrinol Metab. 1972;35(6):775-784. doi:10.1210/jcem-35-6-775
4. Pak CY, Kaplan R, Bone H, Townsend J, Waters O. A simple test for the diagnosis of absorptive, resorptive and renal hypercalciurias. N Engl J Med. 1975;292(10):497-500. doi:10.1056/NEJM197503062921002
5. Neelon FA, Birch BM, Drezner M, Lebovitz HE. Urinary cyclic adenosine monophosphate as an aid in the diagnosis of hyperparathyroidism. Lancet. 1973;1(7804):631-633. doi:10.1016/s0140-6736(73)92199-5
6. Drezner MK, Neelon FA, Curtis HB, Lebovitz HE. Renal cyclic adenosine monophosphate: an accurate index of parathyroid function. Metabolism. 1976;25(10):1103-1112. doi:10.1016/0026-0495(76)90018-4
7. Delrue C, Speeckaert R, Moresco RN, Speeckaert MM. Cyclic Adenosine Monophosphate Signaling in Chronic Kidney Disease: Molecular Targets and Therapeutic Potentials. Int J Mol Sci. 2024;25(17):9441. doi:10.3390/ijms25179441
8. Kaminsky NI, Broadus AE, Hardman JG, et al. Effects of parathyroid hormone on plasma and urinary adenosine 3',5'-monophosphate in man. J Clin Invest. 1970;49(12):2387-95. doi:10.1172/JCI106458
9. Tze WJ, Saunders J, Drummond GI. Urinary 3'5' cyclic AMP. Diagnostic test in pseudohypoparathyroidism. Arch Dis Child. 1975;50(8):656-658. doi:10.1136/adc.50.8.656
10. Ishida M, Seino Y, Simotsuji T, et al. Differential diagnosis of hypoparathyroid disorders during childhood. Calcif Tissue Int. 1980;31(3):203-207. doi:10.1007/BF02407182
11. Mantovani G. Clinical review: Pseudohypoparathyroidism: diagnosis and treatment. J Clin Endocrinol Metab. 2011;96(10):3020-3030. doi:10.1210/jc.2011-1048
Method Description
Acetonitrile is added to urine samples to dilute and precipitate proteins in proteinaceous samples. Next, the sample is further diluted with buffer followed by the addition of internal standard (8-methyl amino cyclic AMP). The resulting supernatant is then injected on the liquid chromatography tandem mass spectrometry instrument, which performs chromatographic separation and target measurement of 3'-5'-cyclic adenosine monophosphate (cAMP). Urine and serum creatinine levels are used to determine the clearance of cAMP from the kidneys.(Unpublished Mayo method)
Creatinine:
The enzymatic method is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Creatinine plus v2. Roche Diagnostics; V15.0, 03/2019)
Day(s) Performed
Wednesday
Report Available
2 to 11 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82030
82570
82565
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CARU | Cyclic Amp, Urinary Excretion | 21052-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 179 | Cyclic Amp, Urinary Excretion | 22712-4 |
| ACREA | Creatinine, S | 2160-0 |
| CRETR | Creatinine, Random, U | 2161-8 |