Differentiating Pulmonary Tuberculosis from Bacterial Pneumonia: The Role of Inflammatory and Other Biomarkers

Introduction:To investigate the values of procalcitonin (PCT) and laboratory parameters in differentiating tuberculosis (TB) pneumonia from community-acquired pneumonia (CAP).Methods:Between 01.01.2018 and 01.01.2020, 4,133 patients diagnosed with CAP or TB pneumonia in a reference hospital for chest diseases and TB were retrospectively screened. Patients with a history of close contact with someone with TB, night sweats, weight loss, or cavitary infiltration that may be typical for TB in the chest X-ray were evaluated clinically and radiologically as high TB suspects and were excluded from the study. Demographic characteristics, comorbidities, medications, admission complaints, radiological findings, microbiology results, and laboratory parameters were recorded. CURB-65 and pneumonia severity index scores were calculated. Patients were grouped as TB (n=70) and CAP (n=506) based on the final diagnosis. The parameters of the two groups were compared.Results:The mean age of 576 patients was 55, and 423 (73%) were male. While sodium (Na) [95% confidence interval (CI): 0.716-0.914, p=0.001], blood urea nitrogen (BUN) (95% CI: 0.910-0.986, p=0.008), alanine aminotransferase (ALT) (95% CI: 0.913-0.998, p=0.043) and oxygen saturation (95% CI: 1.007-1.268, p=0.037) were found as independent biomarkers for differentiating TB and CAP, PCT had no significant influence on the differential diagnosis.Conclusion:Prompt differential diagnosis between TB and CAP is important for public health in endemic TB areas. We recommend the evaluation of Na, ALT, and BUN for this purpose.