Nephrines Plasma ELISA Kit (Metanephrine/Normetanephrine)

INTENDED USE

Human nephrines plasma ELISA kit is a procedure for analysing in vitro quantitative levels of metanephrine/normetanephrine (nephrines) in human plasma samples. This assay has a minimum detection level of 17.0 pg/ml (MN) and 23.0 pg/ml (NMN).

BACKGROUND

Metanephrine and normetanephrine are O-methylated metabolites of the catecholamines epinephrine (E) and norepinephrine (NE) respectively. Both of these can be further metabolised to vanillylmandelic acid. The basic common structure present in both of these molecules is a methylated catechol ring (3-methoxy 4-hydroxy phenyl) in conjunction with an ethylamine group. It is found to possess the higher molecular weight of 197 g/mol which is in contrast to NM that is 183 g/mol. The reason for the difference in molecular weight is due to the presence on a methylated amino group.

These metanephrines have been useful in providing markers of the extraneuronal metabolism of the parent catecholamines. In particular for clinical medicine, it has been vital diagnostic tools for identifying patients that maybe suspected of containing tumors of chromaffin (for example pheochromocytoma and paraganglioma). Both of the metabolites are measured in plasma and urine, where the determination of conjugated-metanephrines in urine has been a long-standing and well-established procedure. Recent, emergence of reliable assay methods for plasma-free-metanephrines has fostered a more extensive assessment of the metabolism of catecholamines.

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• Metanephrine Microtiter Strips.
• Normetanephrine Microtiter Strips.
• Standards (A-F): Concentrations 0, 36, 120, 360, 1,200, 3,600 pg/ml (MN) and 0, 72, 240, 720, 2,400, 7,200 pg/ml (NMN).
• Controls 1.
• Control 2.
• Antiserum – Rabbit anti-metanephrine antibody.
• Antiserum – Rabbit anti-normetanephrine antibody.
• Wash Buffer Concentrate (50x).
• Enzyme Conjugate.
• Substrate (TMB).
• Stop Solution.
• Extraction Plate: Pre-coated with ion-exchanger.
• Adjustment Buffer:
• Acylation Concentrate.
• Assay Buffer.
• Elution Buffer.
• Cleaning Concentrate (25x)
• Equalizing-Reagent.
• Adhesive Foil.

SENSITIVITY

The minimum sensitivity limit of nephrines  (metanephrine/normetanephrine) using current nephrines plasma ELISA kit was approximately 23.0 pg/ml (MN) and 17.0 pg/ml (M). The dynamic range for this assay is 36.0 – 3,600 pg/ml (MN) and 48.0 – 4,800 pg/ml (NMN).

ASSAY CHARACTERISTICS

– Analytical Sensitivity: MN – LOD (14.9 pg/ml) and LOQ (15.1 pg/ml), NMN – LOD (17.9 pg/ml) and LOQ (22.8 pg/ml).
– Analytical Specificity (Cross Reactivity): Highly specific for derivatized metanephrine (100%) and derivatized normetanephrine (100%).
– Intra Assay Precision: 9.2 – 13.5% (MN) and 8.2 – 10.5% (NMN)
– Inter Assay Precision: 7.5 – 17.6% (MN) and 5.0 – 10.6% (NMN)
– Linearity: 101 – 124% (Metanephrine) and 92 – 102% (Normetanephrine)
– Recovery: 80 – 99% (Metanephrine) and 105 – 114% (Normetanephrine)

REFERENCES

1. Assessment of O-methylated catecholamine levels in plasma and urine for diagnosis of autonomic disorders. Auton Neurosci. (2004) 116 (1-2): 1-10. Review. Oeltmann T., et al.
2. Sources and significance of plasma levels of catechols and their metabolites in humans. J Pharmacol Exp Ther. (2003) 305 (3): 800-11. Review. Goldstein D.S., et al.
3. Pheochromocytoma: rediscovery as a catecholamine-metabolizing tumor. Endocr Pathol. (2003) 14 (3): 193-212. Review. Eisenhofer G., et al.
4. Utility of plasma free metanephrines in diagnosis of factitious pheochromocytoma. Endocr Pract. (2006) 12 (5): 568-71. Chidakel A.R., et al.

ADDITIONAL INFORMATION

• Full Name: Nephrines Plasma ELISA Kit (Metanephrine/Normetanephrine)
• Reactivity: Human
• Sample Type: Plasma
• Sensitivity: 17.0 pg/ml (M) and 23 pg/ml (NM)

OTHER RELATED ELISA KITS

• Metanephrine Plasma ELISA Kit
• Normetanephrine Plasma ELISA Kit
• 2-CAT (Adrenaline/Noradrenaline) ELISA Kit