Introduction: White blood cell (WBC) count, from which neutrophil-to-lymphocyte count ratio (NLCR) can be derived, is commonly requested in the hospital setting among admitting patients with community acquired pneumonia (CAP). This study aims to establish the predictive value of WBC count and NLCR in classifying CAP which guides the clinicians in the choice of antibiotics and site-of-care. The researchers aim to evaluate the predictive value of WBC count and NLCR during consultation and admission in classifying patients with CAP based on the managementoriented risk stratification of the 2016 Philippine Clinical Practice Guidelines on CAP. Methods: This was a prospective cross-sectional study conducted in St. Luke’s Medical Center, Quezon City. Adult patients diagnosed with CAP were classified according to severity of infection based on the 2016 Philippine Clinical Practice Guidelines on CAP. WBC count of each patient was determined, and their corresponding NLCR was derived. The differences of WBC count and NLCR per risk were evaluated using chi-square and ANOVA test adjusted for the distribution of the outcome. Sensitivity and specificity of WBC and NLCR were determined for the following: (1) between CAP low risk (LR) versus CAP moderate risk (MR) and CAP high risk (HR) and (2) between CAP LR and CAP MR versus CAP HR. Receiver operating characteristic (ROC) curve was constructed to evaluate the sensitivity and specificity of WBC and NLCR in classifying. ROC curves displayed sensitivity versus 1-specificity such that area under the curve (AUC) ROC for WBC and NLCR. Results: Two hundred eighty (280) CAP patients from June 2016 until April 2017 were studied. Among the CAP patients, 69 (24.6%) were classified as LR, 172 (61.5%) were classified as MR, and 39 (13.9%) were classified as HR. The mean WBC count was 11,725.8 (±5,205.82)/ụl. The mean WBC per risk were as follows: 9,178/ụl for LR; 12,251/ụl for MR, and 13,916/ ụl for CAP HR. It showed that the higher the risk, the higher the mean of the WBC count (<0.00001). The mean NLCR was 8.9 (±8.4). The mean average of NLCR per risk were as follows: 5.4 for LR, 8.6 for MR, and 16.1 for HR. It showed that the higher the risk, the higher the NLCR (<0.00001). In predicting CAP patients with HR and MR from LR, the AUC of NLCR (0.700) was almost the same as that of the WBC count (0.698). In predicting CAP patients with HR from MR and LR, the AUC of NLCR (0.726) was higher than the WBC (0.621), indicating that NLCR is a fair predictive marker in distinguishing HR from MR and LR. Conclusion As the severity of CAP increases, the mean of the WBC count and NLCR increases. Between the two biomarkers, NLCR predicts CAP severity more than the WBC count. Furthermore, NLCR better predicts HR from MR and LR
Leukocyte Count