RESUMO
BACKGROUND: Leukocytes total count is an independent risk marker for cardiovascular events. The ratio between neutrophils and lymphocytes (N/L) count has been investigated as a new predictor for cardiovascular risk, although its diagnostic role when assessing patients suspected of an acute coronary syndrome (ACS) condition is not yet known. OBJECTIVE: To evaluate the diagnostic power of N/L ratio in patients who have been admitted at a Chest Pain Unit (CPU) with the suspicion of ACS. METHODS: Evaluation was conducted in 178 patients admitted with chest pain. Diagnostic flowchart including clinical, electrocardiographic, and laboratory data. Diagnosis obtained was: acute myocardial infarction (AMI) with (AMI-STE) and with no segment T elevation (AMI-NSTE), unstable angina (UA ) and non-cardiac pain (NC). Total and differential leukocyte count was conducted in peripheral blood sample collected at admission. RESULTS: Patients diagnosed with non-cardiac pain reported the lowest N/L ratio (n=45; 3.0 +/- 1.6), followed by UA (n=65; 3.6 +/- 2.9), AMI-NSTE (n=33; 4.8 +/- 3.7) and AMI-STE (n=35; 6.9 +/- 5.7); p < 0.0001. N/L ratio above 5.7 (highest quartile) reported 91.1% specificity, 4.51 odds ratio (CI 95% 1.51 to 13.45) for the final diagnosis of ACS when compared to the groups at lower quartiles. CONCLUSION: The N/L ratio presents correlation with final diagnosis of patients with suspicion of ACS at admission. Considering this is a low cost, good reproductibility test, new studies should ellucidate whether the ratio may be of relevance for diagnosis flowcharts currently in use.