Diagnostic performance of host protein signatures as a triage test for active pulmonary TB

The current four symptom screen recommended by the WHO is widely used as screen to initiate diagnostic testing for active pulmonary tuberculosis (TB), yet the performance is poor especially when TB prevalence is low. In contrast, more sensitive molecular tests are less suitable for the placement at primary care level in low resource settings. In order to meet the WHO End TB targets new diagnostic approaches are urgently needed to find the missing undiagnosed cases. Proteomics-derived blood host biomarkers have been explored because protein detection technologies are suitable for the point-of-care setting and could meet cost targets.This study aims to find a biomarker signature that fulfills WHO’s target product profile (TPP) for a TB screening. 12 blood-based protein biomarkers from three sample populations (Vietnam, Peru, South Africa) are analyzed individually and in combinations via advanced statistical methods and machine learning algorithms. The combination of I-309, SYWC and kallistatin shows the most promising results for TB prediction throughout the datasets meeting the TPP for a triage test in adults from two countries (Peru and South Africa). The top performing individual markers identified at the global level (I-309 and SYWC) were also among the best performing markers at country level in South Africa and Vietnam.This analysis clearly shows that a host protein biomarker assay is feasible in adults for certain geographical regions based on one or two biomarkers with a performance that meets minimal WHO TPP criteria.Abstract ImportanceTuberculosis (TB) remains a serious worldwide health problem and diagnosis is hampered by the complexity of tests at primary care level in low resource settings or the low accuracy for screening settings. In order to meet the WHO End TB targets new diagnostic approaches are urgently needed to find the missing undiagnosed cases.This analysis clearly shows that a host protein biomarker assay is feasible in adults for certain geographical regions. We were able to construct an algorithm through statistical methods and machine learning algorithms whose performance meets the minimum of the WHO target product profile criteria. Thus, further work should be addressed at demonstrating that such as assay can be translated into a practical point-of-care test, and to better understand how to address regional differences in biomarker levels and responses.