Dopamine, Plasma

Test Code

14762

CPT Codes
82542

Preferred Specimen

2 mL plasma collected in a sodium heparin (green-top) tube - See instructions

Patient Preparation
Patients should be relaxed in either a supine or upright position before blood is drawn. States of anxiety and stress can cause fluctuations in the catecholamine levels.
Patient should avoid alcohol, coffee, tea, tobacco and strenuous exercise prior to collection. Overnight fasting is preferred.

Minimum Volume

1 mL

Other Acceptable Specimens

Plasma collected in an EDTA (lavender-top) tube - See instructions

Instructions

Draw specimen in a pre-chilled green-top vacutainer. Plasma should be separated in a refrigerated centrifuge within 30 minutes of collection and then frozen immediately at -20°C in plastic vials. Each specimen will be invoiced separately.

Transport Container

Plastic screw-cap vials

Transport Temperature

Frozen

Specimen Stability

Room temperature: 6 hours
Refrigerated: 6 hours
Frozen: 31 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis

Methodology
Liquid Chromatography/Mass Spectrometry (LC/MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Mon-Fri; Report available: 4-7 days

Reference Range

Dopamine, Plasma

<18 years	No Reference Range Available
≥18 years	Supine: <16 pg/mL Upright: <27 pg/mL

Clinical Significance

Measurement of dopamine levels in urine or blood in addition to urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) levels may aid in the biochemical diagnosis and monitoring of neuroblastomas [1]. This test may also be useful in evaluating dopamine-secreting pheochromocytomas and paragangliomas (PPGLs) [2].

Neuroblastomas occur predominantly in children and are the most common malignancy under 1 year old. Neuroblastomas are catecholamine-metabolizing tumors, and thus catecholamine metabolites (including VMA and HVA) are more reliable than catecholamines as biochemical markers for neuroblastomas [1]. However, urinary VMA and HVA levels may have limited accuracy for diagnosis of neuroblastomas with high-risk metastatic biology [1]. Because poor prognosis is associated with immaturity of catecholamine metabolism, dopamine levels in urine or blood have been proposed as an additional marker to aid in diagnosis and monitoring of neuroblastomas [3].

Most PPGLs secrete catecholamines, but the relative amount of dopamine, norepinephrine, and epinephrine varies widely. Measurements of plasma free or urinary fractionated metanephrines (ie, the O-methylated catecholamine metabolites) are recommended by the Endocrine Society for the initial biochemical testing of PPGLs [4]. In patients with high clinical suspicion but normal blood pressure and normal levels of metanephrines, measurement of dopamine and its metabolites (HVA and methoxytyramine) may help diagnose PPGLs that predominantly secrete dopamine [2].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Eisenhofer G. Monoamine-producing tumors. In: Rifai R, et al. eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
2. Jain A, et al. Pediatr Nephrol. 2020;35(4):581-594.
3. Brodeur GM, et al. J Clin Oncol. 1993;11(8):1466-1477.
4. Lenders JW, et al. J Clin Endocrinol Metab. 2014;99(6):1915-1942

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.