Background: Influenza A (H1N1) infection has been causing significant morbidity and mortality since 2009 epidemic all over the world. There needs to be rapid isolation of suspected patient to prevent further spread. Real-time polymerase chain reaction is a time consuming and costly test to confirm the diagnosis. There is a need of rapid and simple diagnostic test for H1N1.
Objective: The study was done to evaluate the utility of neutrophillymphocyte ratio and lymphocytemonocyte ratio as screening tool for suspected H1N1 cases.
Material and Methods: This was a retrospective study in which confirmed H1N1 cases from isolation ward for influenza were identified. Data were recorded in validated case record form. All the data regarding clinical history, examination findings, X-ray, and blood count were collected from case records of patients. Negative H1N1 cases were excluded from the study.
Result: Mean age of patients was 27.7 year. Mean duration of stay was 5.85 days with range of 38 days. The most common symptoms were cough and sore throat (79.41%), fever (76.47%), and breathlessness (47.05%). Low WBC count was observed only in two patients (5.88%) Polymorphonuclear predominance was observed in 21 patients (61.76%). Polymorphonuclear to lymphocyte ratio was >2 in 21 patients and lymphocyte-to-monocyte ratio was observed >2 in 33 patients.
Conclusion: PL ratio and LM ratio cannot be used as criteria of exclusion of H1N1 infection because of higher prevalence of secondary bacterial infection. This needs to be further evaluated in larger patient population.
Key words: Polymorphonuclear-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, RT-PCR, H1N1