Table 1.
TPP: A rapid biomarker-based non-sputum–based test for detecting TB
| Characteristic | Optimal requirements | Minimal requirements |
| Scope | ||
| Goal | To 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 population | Target 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 test | Health-care workers with a minimum of training | Trained 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 system | Primary 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 infection | Overall ≥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 adults | Ideally, should be ≥80% for all forms of microbiologically confirmed TB | No lower range of sensitivity was defined |
| Diagnostic sensitivity in children | Sensitivity for intrathoracic TB ≥66% for microbiologically confirmed TB (that is, similar to Xpert MTB/RIF) | No lower range of sensitivity was defined |
| Diagnostic specificity | At 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 type | Not invasive or minimally invasive, non-sputum samples | |
| Manual preparation of samples | Sample prep should be integrated or manual prep should not be required | Limited 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 requirement | No instrument needed | Small, portable or hand-held instrument that can operate on battery or solar power |
| Maintenance and calibration | Disposable, no maintenance | Minimal 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 display | Instrument free test with ability to save test results using separate, attachable reader | Test menu must be simple to navigate; integrated screen, simple keypad or touch screen, ability to save results using instrument or separate reader |
| Internal quality control | Internal controls included for processing sample and detecting TB | Internal control only for processing sample |
| Price | ||
| Price of individual test | <US $4.00 | <US $6.00 |