Mycobacterium tuberculosis is a frequent cause of community-acquired pneumonia (CAP), and the differential diagnosis of tuberculosis (TB) from bacterial pneumonia is difficult in areas with a high TB burden. We investigated the usefulness of serum C-reactive protein (CRP) and procalcitonin (PCT) in differentiating pulmonary TB from bacterial CAP in South Korea, a country with intermediate TB burden.
We conducted a prospective study, enrolling 87 participants with suspected CAP in a community-based referral hospital in South Korea. Before treatment, a clinical assessment was performed and serum CRP and PCT were measured. The test results were compared to the final diagnoses.
Of the 87 patients, 57 had bacterial CAP and 30 had pulmonary TB. The median CRP concentration was 14.58 mg/dL (0.30–36.61) in patients with bacterial CAP and 5.27 mg/dL (0.24–13.22) in patients with pulmonary TB (p<0.001). The median PCT level was 0.514 ng/ml (0.01–27.75) with bacterial CAP and 0.029 ng/ml (0.01–0.87) with pulmonary TB (p<0.001). There was no difference in the discriminative values of CRP and PCT (p=0.733). However, PCT differed according to pneumonia severity index I-II versus III-V in bacterial CAP. (0.16 vs. 0.66 ng/ml, p=0.012).
The concentrations of CRP and PCT differed significantly in patients with pulmonary TB and bacterial CAP. The high sensitivity and negative predictive value in differentiating pulmonary TB from bacterial CAP suggest a supplementary role of CRP and PCT for the diagnostic exclusion of pulmonary TB from bacterial CAP in areas with an intermediate prevalence of pulmonary TB.
Sensitivity and specificity of CRP and procalcitonin for the diagnosis of pulmonary TB from community-acquired pneumonia were tested. The serum concentrations of CRP and procalcitonin differed significantly in patients with pulmonary TB and bacterial CAP in areas with an intermediate prevalence of active pulmonary TB.
Ji Young Son, No Financial Disclosure Information; No Product/Research Disclosure Information