Composite Bacterial Infection Index and Serum Amyloid A Protein in Pulmonary Tuberculosis Patients and their Household Contacts in Makassar

BACKGROUND: Early diagnosis of tuberculosis (TB) cases in limited resource remains challenging. It is urgent to identify the new diagnostic tools which can control the spread of disease with accurate and rapid test. AIM: This study aimed to investigate the levels of infection markers: Composite bacterial infection index (CBII) and serum amyloid A (SAA) protein in pulmonary TB (PTB), and their healthy household contacts, as the alternative diagnostic markers for TB. METHODS: CBII and SAA were measured from 44 new PTB patients, and 31 household contact serum samples. The value of CBII was calculated from neutrophils, lymphocytes, monocytes, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein (hs-CRP) level. hs-CRP and SAA levels were quantified from their serum samples using ELISA. QuantiFERON-TB Gold Plus (interferon gamma release assay [IGRA]) was used to screen latent TB infection among household contacts. RESULTS: Among 31 household contacts, there were 24 positive IGRA results and the rest (n = 7) had negative results. PTB patients exhibited significantly higher level CBII in the serum specimens, than those in household contact (p < 0.0001). There was no significant difference in the SAA level between TB cases and household contacts (p = 0.679). CONCLUSIONS: CBII can be used as one of the biomarkers for the identification of PTB from the serum specimens.