title: Differential diagnosis of chest pain in an emergency department: the value of homocysteinemia as a diagnostic marker.
abstract: Only 20 to 45% of patients (pts) admitted to an emergency department (ED) with chest pain (CP) have a cardiac ischemic CP (ICP). Apart from the need for a rapid detection of ICP cases, it is important to avoid discharging patients with false negative ICP. We studied the capability of plasma homocysteine (Hcy) values to improve the differential diagnosis (DD) in patients admitted to an ED with CP.
  
  
  METHODS
  125 patients, 80 males, mean age 61 yrs (25-96 yrs), 75 (60%) without prior atherosclerotic cardiovascular disease (ACVD), consecutively admitted to the ED with CP which was not immediately clear. Definitive diagnosis: ICP-58 patients (46%); non-ischemic (non-ICP)--64 patients (54%).
  
  
  METHODS
  Hcy was measured on admittance (fasting state not required), by means of a fluorescence polarization enzyme immunoassay (IMx, Abbott); at real conditions, the results were obtained within 2 hours (but not displayed).
  
  
  RESULTS
  1) Hcy (mumol/L) = 10.9 +/- 5.4 (non ICP without prior CDAV); 13.9 +/- 7.7 (ICP). 2) Hcy > or = 15.0 mumol/L in patients without prior ACVD: 5 patients (9%) with non ICP, 8 patients (38%) with ICP--p < 0.01; RR = 2.9 (95% CI = 1.2-7.1); positive value = 62%; negative predictive value = 79%.
  
  
  CONCLUSIONS
  In patients without ACVD, Hcy may contribute to improve DD of equivocal CP, namely: 1) before a normal or non-diagnostic ECG and negative ischemia markers, Hcy > or = 15.0 mumol/L will imply additional cardiological investigation in the ED; 2) Hcy < 15.0 increases the liability of a non-ICP diagnosis.
authors.affiliation: Serviço de Urgência Central, Hospital de Santa Maria, Lisboa.
authors.forename: A D
authors.initials: AD
authors.lastname: Bordalo
authors.forename: B G
authors.initials: BG
authors.lastname: Pinto
authors.forename: C F
authors.initials: CF
authors.lastname: Andrade
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000097:blood / Q000209:etiology*; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D015203:Reproducibility of Results
chemical_list: D015415:Biomarkers; D006710:Homocysteine