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HelpMayo Test ID CARU Cyclic Adenosine Monophosphate (cAMP), Urinary Excretion, Serum and Urine
Specimen Required
Both serum and urine are required. Serum must be obtained at the time of the urine collection.
Specimen Type: Serum
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
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: 2.0 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| 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
Adenosine cyclic 3',5'-monophosphate (cAMP) functions as an intracellular "second messenger" regulating the activity of intracellular enzymes or proteins in response to a variety of hormones (eg, parathyroid hormone).
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
Urinary adenosine cyclic 3',5'-monophosphate (cAMP) is elevated in about 85% of patients with hyperparathyroidism and in about 50% of patients with humoral hypercalcemia of malignancy.
Cautions
Parathyroid suppression (hypoparathyroidism) does not lower urinary adenosine cyclic 3',5'-monophosphate (cAMP) excretion to definitively subnormal values.
Clinical Reference
1. Aurbach GD, Marx SJ, Spiegel AM: Parathyroid hormone, calcitonin, and the calciferols. In: Wilson JD, Foster DW, eds. Williams Textbook of Endocrinology. 8th ed. WB Saunders Company; 1992:1413-1415
2. Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Elsevier; 2020
Method Description
Adenosine 3',5'-cyclic monophosphate (cAMP) is isolated from the urine using a single anion exchange column. An internal standard (8-methyl amino cAMP) is used to correct for recovery losses. Once the cAMP has been eluted from the column, it is added to a solution and injected onto the liquid chromatography tandem mass spectrometry system. Quantitation is by peak area measurement against a calibration standard containing known quantities of cAMP and internal standard. 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 10 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 |