Simple, rapid and sensitive determination of epinephrine and norepinephrine in urine and plasma by non-competitive enzyme immunoassay, compared with HPLC method.

Abstract

BACKGROUND: Measurement of the concentration of the free catecholamines epinephrine (adrenalin) and norepinephrine (noradrenalin) in humans is used for the diagnosis of pheochromocytoma and related diseases. METHODS: A non-competitive enzyme-linked immunosorbent assay (CatCombi ELISA) kit for the measurement of epinephrine and norepinephrine concentrations in plasma and urine was developed and validated. The assay procedure consists of sample extraction, chemical and enzymatic derivatization and immunological reaction steps. A sample volume of 10 microL urine or 300 microL EDTA plasma is required for duplicate determinations of both catecholamines. For method comparison we used a reversed phase HPLC by Chromsystems after extraction by aluminium oxide with electrochemical detection for the determination of epinephrine and norepinephrine. RESULTS: The CatCombi ELISA is accurate, sensitive, specific, and precise. Linear regression analysis of epinephrine and norepinephrine concentrations measured with the ELISA and with HPLC yielded highly significant correlations. CONCLUSIONS: The CatCombi ELISA kit as an alternative to HPLC methods is very useful for clinical applications as well as for basic research where a simple, rapid, accurate and reproducible assay for epinephrine and norepinephrine determinations is required.