Free plasma metanephrines as a screening test for pheochromocytoma in low-risk patients.

OBJECTIVES: Detection of free plasma metanephrines seems to be the most exact method for biochemical diagnosis of pheochromocytoma, but their diagnostic efficacy in the common low-risk clinical settings is debated. METHODS: A cross-sectional multicentre study including 1260 subjects assessed the diagnostic efficacy of free plasma metanephrine and normetanephrine in low-risk patients screened for resistant or markedly accelerated hypertension, paroxysmal hypertension, 'flushes' and, in a small proportion, for adrenal incidentaloma or genetic predisposition to pheochromocytoma. RESULTS: Pheochromocytoma was identified and verified by histology in 25 subjects (2%), with the diagnosis not confirmed by long-term follow-up or use of imaging techniques in the remaining 1235 individuals. The combined assay of free plasma metanephrines was a highly sensitive (100%) and specific (96.7%) measure, yielding a negative predictive value of 100%. CONCLUSION: The satisfactory diagnostic efficacy of free plasma metanephrines allows their use as a single screening test in cases of suspected pheochromocytoma in the population with a low pretest probability.

Use of glycogen phosphorylase BB measurement with POCT in the diagnosis of acute coronary syndromes. A comparison with the ELISA method.

BACKGROUND: Glycogen Phosphorylase BB (GPBB) is considered an early and specific marker of myocardial necrosis and ischemia. A POCT kit GPBB for diagnostic use has recently been approved. AIM: an evaluation of the correspondence of qualitative POCT GBPP measurements with ELISA test results. MATERIAL AND METHODOLOGY: 20 individuals with non-ST elevation myocardial infarction (non-STEMI) and 20 probands without acute coronary syndrome (ACS) were tested. GPBB (POCT, ELISA) in venous plasma (lithium-heparin) was assayed in all probands. RESULTS: individuals with non-STEMI had significantly higher GPBB ELISA values (32.3 vs. 6.1 microg/l; p < 0.01). GPBB sensitivity and specificity for non-STEMI presence 6 hours after chest pain generation were 100 %. No proband was classified in a different subgroup with POCT of GPBB (positive/negative). GPBB POCT correlate with a non- STEMI diagnosis (chi(2) 36.1; p <0.01). CONCLUSION: GPBB POCT measurement is comparable with ELISA test results. GPBB analysis could expand the diagnostic palette in the first hours after the onset of acute coronary syndrome.