DROP-TB: Dried Blood Spot Test to Assess TB in Pregnancy in Remote and Resource Limited Areas

The Drop-TB program aims to expand the reach of TB testing in pregnancy by creating a system where DBS samples are collected from women at their local healthcare clinics instead of at national-level TB diagnostic centers where visits can require substantial travel and cost. A DBS is collected from a pregnant woman with suspected TB using a finger prick blood sample4 (cover photo) and transported to a central TB testing facility and analyzed by real-time polymerase chain reaction (qPCR)5. Drop-TB uses 3G-qPCR to measure mRNA expression of three genes (3G)6 known to be markers of TB infection. The 3G signature indicates the host response to infection through a ratio of the three target genes that show elevated transcription when a patient is infected with TB and therefore does not test for bacteria-derived DNA and can be used to diagnose pulmonary TB without disseminated infection. This enables testing using a peripheral blood sample with performance comparable to sputum or intravenous blood sample.