Serum Procalcitonin as a Biological Marker to Distinguish between Bacterial and Non-Bacterial Exacerbation of COPD: A Comparative Cross- Sectional Study at a Tertiary Care Centre in India

Aims: The goal of this study was to determine the diagnostic importance and cut-off value of serum PCT as a vital biomarker in differentiating bacterial and non-bacterial causes of exacerbation of COPD. Study Design:  It was a comparative cross-sectional study. Place and Duration of Study: Study was conducted on 80 patients recruited from VMMC and Safdarjung Hospital, New- Delhi, India, for a period of 18 months. Forty  patients has COPD and other 40 had acute exacerbation of COPD. Methodology: Every enrolled patient received a thorough history, a clinical assessment, and records of tests such as a venous blood sample, spirometry, and a chest X-ray. We excluded from our study patients with various respiratory conditions such as hydrothorax, pneumothorax, CHF, pleural effusion, and those outside the respiratory system, as well as those who started antibiotic medication earlier than 48 hours after enrollment. Venous samples were obtained from each participant in order to measure procalcitonin levels and blood counts. Serum PCT levels were assessed by ELISA kit. Gram stain and culture was done of sputum sample collected from the exacerbated group. Results: Patients with bacterial COPD exacerbations had significantly higher mean serum PCT levels compared to non-bacterial exacerbations (2.58±1.54 vs 0.45±0.51 ng/ml; P=0.0001) based on sputum culture results. PCT cutoff of 0.9 ng/ml differentiated bacterial exacerbations with 100% sensitivity and 76.9% specificity. Conclusion: The findings of the study indicate the serum PCT levels can be regarded as an appropriate biomarker to differentiate between the bacterial and non-bacterial cause of exacerbation in COPD.