CARDIAC TROPONIN-I AND TROPONIN-T IN PATIENTS WITH SUSPECTED ACUTE CORONARY SYNDROME - A COMPARATIVE-STUDY IN A ROUTINE SETTING

We compared cardiac troponin I (cTnI), using Access(R), Sanofi Pasteur , and cardiac troponin T (cTnT), using Elecsys(R), Boehringer Mannheim , in the first two routine blood samplings in a routine panel of cardi ac markers for the biochemical diagnostic evaluation of patients with symptoms of acute myocardial infarction (AMI). No significant differen ces in the overall clinical performances of cTnI and cTnT were observe d for the diagnosis of AMI (n = 68), but cTnI demonstrated lower initi al sensitivity and higher specificity compared with cTnT. cTnT was inc reased to higher relative values than cTnI (P = 0.023). Discordances w ere found between cTnI and cTnT in sample I but not in sample II; posi tive cTnT/negative cTnI was more common than the opposite discordance (P = 0.027). cTnT was more frequently increased in patients with unsta ble angina pectoris (UAP) than cTnI (P = 0.038), with no significant d ifferences between sample I and sample II; discordant results with res pect to cTnI and cTnT appeared in 6 (33%) of these patients, all of wh ich were positive for cTnT and negative for cTnI. Four patients with U AP (22%) developed AMI within 4 months; three were associated with inc reased cTnI and cTnT at the time of initial testing, and one was disco rdant (positive cTnT). In patients classified with no acute coronary s yndrome (n = 84), five concordant positives for cTnI and cTnT were obs erved, indicating the existence of a myocardial injury of recent origi n in these patients. AMI evolved in one of these patients 5 months lat er. We conclude that cTnT and cTnI detect acute myocardial injury with equal clinical performance in AMI patients classified by WHO criteria . cTnT was more frequently increased in patients with UAP than cTnI, b ut the clinical significance of this discordance could not be determin ed from this study.