Quantification of Unconjugated Metanephrines in Human Plasma without Interference by Acetaminophen

Quantification of unconjugated metanephrines in human plasma without interference by acetaminophen.

BACKGROUND Pheochromocytoma is a rare cause of hypertension resulting from increased catecholamine secretion. We aimed to develop a method to measure unconjugated plasma normetanephrine (NMN) and metanephrine (MN) without interference from acetaminophen, a widely prescribed drug for headaches. METHODS Plasma samples were obtained from 48 subjects (23 males, 25 females; mean age, 49 +/- 14 yea...

Plasma Metanephrines in the Diagnosis of Pheochromocytoma

Rapid colorimetric assay for acetaminophen without salicylate or phenylephrine interference.

A simple rapid, and economical procedure is presented for the quantitative determination of acetaminophen in serum. Acetaminophen is extracted into solvent, and, when back-extracted into base, is simultaneously reacted with Folin-Ciocalteau reagent to form a colored complex. The potential interference of bilirubin is eliminated by treatment with p-diazobenzene sulfonic acid. Results obtained wi...

Plasma metanephrines in the diagnosis of pheochromocytoma.

OBJECTIVE To examine whether tests for plasma metanephrines, the o-methylated metabolites of catecholamines, offer advantages for diagnosis of a pheochromocytoma over standard tests for plasma catecholamines or urinary metanephrines. DESIGN Cross-sectional study. SETTING 3 clinical specialist centers. PATIENTS 52 patients with a pheochromocytoma; 67 normotensive persons and 51 patients wi...

Quantification of Human Chorionic Gonadotropin by Bovine Serum Albumin Nanoparticles

Background and Aims: Some nanoparticles can be used in immunoassays to increase sensitivity. This study aimed to evaluate a novel nano-immunoassay based on bovine serum albumin nanoparticles (BSA NPs). Materials and methods: At first, the nanostructure was synthesized, and then applied as a tag in the nano-immunoassay. Then the concentration of β-subunit of human chorionic gonadotropin ...