Metanephrines, Fractionated, Free, LC/MS/MS
| Alternate Names | Metanephrines, Fractionated, LC-MS/MS, Plasma, Free Metanephrines |
| Ordering Recommendation | Normetanephrine (NM) and Metanephrine (MN) are the extra-neuronal Catechol-O-Methyl Transferase (COMT) metabolites of the catecholamines norepinephrine and epinephrine, respectively. Measurement of plasma metanephrines is more sensitive (but may be less specific) than measurement of catecholamines for the detection of pheochromocytoma. Proper interpretation of results requires awareness of recent medication/drug history (e.g., antihypertensive agents, alcohol, cocaine) and other pre-analytical factors (e.g., stress, severe congestive heart failure, myocardial infarction) that influence release of catecholamines and metanephrines. |
| Specimen | EDTA Plasma |
| Container Type | Lavender Top Tube
|
| Tests Included | Metanephrine, Free Normetanephrine, Free Total, Free (MN+NMN) |
| Reference Range | See patient report |
| Stability | 14 days |
| Transport Temp | Refrigerate 2°-8°C |
| Instructions | Patients should be relaxed in either a supine or upright position before blood is drawn. Patient should avoid alcohol, coffee, tea, tobacco and strenuous exercise prior to collection. Overnight fasting is preferred.
Draw specimen in a pre-chilled lavender top tube. The whole blood sample should be kept on wet ice until centrifuged (preferably at 4° C) to separate the plasma within 2 hours of venipuncture. After centrifugation, the plasma should be transferred to a transport tube and immediately refrigerated. |
| Performing Lab | Quest Nichols Institute – San Juan Capistrano, CA 92675 Reference Lab Test Code: 19548 |
| Days Performed | Mon-Sat |
| Report Available | 5-6 days |
| NY State Available | Yes |
| LOINC Code | 38494-1, 57462-4, 29142-7 |
| CPT Code | 83835 |
