Studies from Brigham and Women's Hospital in the area of cardiology published.

"To determine whether an ultrasensitive assay can permit quantification of changes in circulating cardiac troponin (Tn) in the setting of stress test-induced myocardial ischaemia. Blood samples were obtained before, immediately after, and 2 and 4 h after stress testing with nuclear perfusion imaging in 120 patients," scientists writing in the European Heart Journal report (see also Cardiology).

"Troponin was measured using commercial assays as well as with a novel, ultrasensitive cardiac TnI assay with a limit of detection of 0.2 pg/mL. Using the ultrasensitive assay, TnI was detectable in all patients before stress testing (median 4.4 pg/mL, interquartile range 3.1-8.6 pg/mL). By 4 h, troponin levels were unchanged in patients without ischaemia, whereas circulating levels had increased by a median of 1.4 pg/mL (24% increase) in patients with mild ischaemia (P = 0.002) and by 2.1 pg/mL (40% increase) in patients with moderate-to-severe ischaemia (P = 0.0006). In contrast, changes in troponin levels across patients in different ischaemic categories were indistinguishable using commercial troponin assays. When added to clinical factors, a> 1.3 pg/mL increase in TnI using the ultrasensitive assay was an independent predictor of ischaemia (odds ...