Table 1.

TPP: A rapid biomarker-based non-sputum–based test for detecting TB

CharacteristicOptimal requirementsMinimal requirements
GoalTo develop a rapid biomarker-based test that can diagnose pulmonary TB and optimally also extrapulmonary TB using non-sputum samples (for example, urine, blood, oral mucosal transudates, saliva, exhaled air) for the purpose of initiating TB treatment during the same clinical encounter or on the same day
Target populationTarget groups are adults and children including those who are HIV-positive and suspected of having active pulmonary TB or extrapulmonary TB in countries with a medium to high prevalence of TB as defined by WHO
Target user of testHealth-care workers with a minimum of trainingTrained microscopy technicians
Setting (level of the healthcare system)Health posts without attached laboratories (that is, levels below microscopy centers) or higher levels of the health-care systemPrimary health-care clinics with attached laboratories; peripheral microscopy centers or higher levels of the health-care system
Performance characteristics
Diagnostic sensitivity for pulmonary TB in adults≥98% for smear positive culture positive TB, ≥68% for smear negative culture positive TB (that is, similar to Xpert MTB/RIF assay) Overall pooled sensitivity should be ≥80% in adults with HIV infectionOverall ≥65% but should be >98% among patients with smear positive culture positive TB (that is, similar to smear microscopy) Overall pooled sensitivity should be better than smear microscopy in adults with HIV infection
Diagnostic sensitivity for extrapulmonary TB in adultsIdeally, should be ≥80% for all forms of microbiologically confirmed TBNo lower range of sensitivity was defined
Diagnostic sensitivity in childrenSensitivity for intrathoracic TB ≥66% for microbiologically confirmed TB (that is, similar to Xpert MTB/RIF)No lower range of sensitivity was defined
Diagnostic specificityAt least as specific as Xpert MTB/RIF for pulmonary, extrapulmonary, and childhood TB (that is, 98% specificity compared against microbiological reference standard); test should distinguish between active TB and latent or past infection
Operational characteristics
Sample typeNot invasive or minimally invasive, non-sputum samples
Manual preparation of samplesSample prep should be integrated or manual prep should not be requiredLimited number of steps only; precise measuring should not be needed
Time to result<20 min including time spent preparing sample<1 h including time spent preparing sample
Instrument and power requirementNo instrument neededSmall, portable or hand-held instrument that can operate on battery or solar power
Maintenance and calibrationDisposable, no maintenanceMinimal maintenance required with automatic alert and remote calibration
Operating temperature and humidity level+5°C to +50°C with 90% humidity+5°C to +40°C with 70% humidity
Results capturing, documentation, data displayInstrument free test with ability to save test results using separate, attachable readerTest menu must be simple to navigate; integrated screen, simple keypad or touch screen, ability to save results using instrument or separate reader
Internal quality controlInternal controls included for processing sample and detecting TBInternal control only for processing sample
Price of individual test<US $4.00<US $6.00