Drug interference with measurement of metanephrines in urine.
نویسندگان
چکیده
The influence of 35 commonly used drugs on measurement of metanephrines in urine was evaluated. Two concentrations of drugs were chosen for study based on usual doses and the percent of dose excreted unchanged in the urine. At "medium" drug concentrations, only phenylephrine falsely elevated metanephrine levels, whereas at a 10-fold higher drug concentration, guanethidine, hydrocortisone, imipramine, isoetharine, levodopa, phenobarbital, and phenylephrine caused positive interference. Propranolol and theophylline caused a negative interference at the two concentrations studied. The significance of these results is discussed.
منابع مشابه
Reflections on a Controversy
The optimal evaluation of patients suspected of having a pheochromocytoma remains controversial. The availability of large numbers of hormone assays and the need to exclude with certainty a potentially lethal disorder with an unpredictable course have led to various approaches to biochemical testing. The quantification of the urinary excretion rate of catecholamine and catecholamine metabolites...
متن کاملDiagnosis of pheochromocytoma. Reflections on a controversy.
The optimal evaluation of patients suspected of having a pheochromocytoma remains controversial. The availability of large numbers of hormone assays and the need to exclude with certainty a potentially lethal disorder with an unpredictable course have led to various approaches to biochemical testing. The quantification of the urinary excretion rate of catecholamine and catecholamine metabolites...
متن کاملFreedom from drug interference in new immunoassays for urinary catecholamines and metanephrines.
BACKGROUND Determination of urinary free catecholamine and total (i. e., free plus conjugated) metanephrine excretion is considered the most clinically sensitive biochemical test for pheochromocytoma. In this study, we evaluated new immunoassay methods for the measurement of these analytes for potential drug-based interference. METHODS Urine samples collected from patients on a variety of med...
متن کاملRapid analysis of metanephrine and normetanephrine in urine by gas chromatography-mass spectrometry.
BACKGROUND Widely used HPLC methods for quantification of metanephrine and normetanephrine in urine often have long analysis times and are frequently plagued by drug interferences. We describe a gas chromatography-mass spectrometry method designed to overcome these limitations. METHODS Metanephrine and normetanephrine conjugates were converted to unconjugated metanephrine and normetanephrine ...
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CONTEXT The initial diagnosis of pheochromocytoma relies on plasma fractionated metanephrines levels. Normal levels exclude pheochromocytoma, but positive tests have a low positive predictive value due to the disease's rarity. OBJECTIVES The objective of the study was to evaluate three approaches to distinguish between true-positive and false-positive tests: 1) increased cutoff for plasma fra...
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عنوان ژورنال:
- Annals of clinical and laboratory science
دوره 13 1 شماره
صفحات -
تاریخ انتشار 1983