title: Cardiac troponin I and creatine kinase MB isoenzyme in patients with chronic renal failure.
abstract: OBJECTIVE
  The aim of our study was to evaluate cut-off values for acute coronary syndrome (ACS) diagnosis in patients with chronic renal failure (CRF) for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase MB isoenzyme (CK-MB) as compared to the cut-off values proposed by the manufacturers and those frequently used in the laboratory.
  
  
  METHODS
  We performed a prospective study in patients with CRF with a glomerular filtration rate estimated by the MDRD-4 equation <60 mL/min and admitted with suspected acute coronary syndrome due to clinical history, physical examination, and electrocardiography. cTnI and CK-MB measurements were assessed upon hospitalisation and six months later using two different analytical methods (for cTnI: Access® and Vidas® analysers, and for CK-MB: Access® and Vitros® analysers).
  
  
  RESULTS
  During the study period, 484 patients with CRF and suspected ACS were assessed. ACS was diagnosed in 12% of patients (58/484), while we found other cardiac pathologies (OCP) in 29% of patients (140/484) and other non-cardiac pathologies (ONCP) in 59% of patients (286/484). For cTnI assessed using the Access® analyser with the usual cut-off value (≥ 0.5 ng/mL), sensitivity was 43% and specificity was 94%, while for the proposed cut-off value (≥ 0.11 ng/mL), the values were 68% and 83%, respectively. For cTnI assessed using the Vidas® analyser with the usual cut-off value (≥ 0.11 ng/mL), sensitivity was 64% and specificity was 87%, while for the proposed cut-off value (≥ 0.06 ng/mL), the values were 75% and 79%, respectively. The sensitivity and specificity for both CK-MB were lower compared with cTnI.
  
  
  CONCLUSIONS
  The cut-off values proposed in this study for both cTnI in patients with CRF (stage 3 to 5) to diagnose ACS are significantly different from that of the general population.
authors.affiliation: Laboratorio de Análisis Clínicos. Complejo Hospitalario de Ourense, Spain. lmlab7@yahoo.es
authors.forename: Larry M
authors.initials: LM
authors.lastname: Flores-Solís
authors.forename: Juan L
authors.initials: JL
authors.lastname: Hernández-Domínguez
authors.forename: Alfonso
authors.initials: A
authors.lastname: Otero-González
authors.forename: José R
authors.initials: JR
authors.lastname: González-Juanatey
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D052279:Creatine Kinase, MB Form / Q000097:blood*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I; D052279:Creatine Kinase, MB Form