Technology Comparisons
Compare diagnostic technologies
No single technology is "always better" — each answers a different clinical question. These tables show where each method fits in the diagnostic pathway.
Tuberculosis diagnostics
Each step answers a different question — they are complementary, not competing.
| Feature | Smear microscopy | GeneXpert | LPA | MGIT culture | WGS |
|---|---|---|---|---|---|
| Turnaround | Hours | ≈ 2 hours | 1–2 days | Days–weeks | Days–weeks |
| Detects TB | AFB only | MTB complex | MTB complex | Viable growth | From isolate/DNA |
| Resistance info | None | Rifampicin | INH + RIF (+ 2nd-line) | Full phenotypic DST | Comprehensive genotypic |
| Viability / AST | No | No | No | Yes | Isolate needed |
Respiratory infection
Rapid antigen tests trade sensitivity for speed; multiplex PCR maximises breadth.
| Feature | Rapid antigen | Culture | PCR | Multiplex PCR |
|---|---|---|---|---|
| Turnaround | Minutes | Days | Hours | Hours |
| Scope | Single pathogen | Bacteria/fungi that grow | Single target | Many pathogens at once |
| Sensitivity | Low–moderate | Variable | High | High (target-specific) |
Antimicrobial resistance
Molecular detection predicts resistance mechanisms; phenotypic AST measures actual drug activity.
| Feature | Disk diffusion | MIC methods | Molecular AMR | WGS |
|---|---|---|---|---|
| Measures | Zone of inhibition | Minimum inhibitory concentration | Resistance genes/mutations | All known resistance loci |
| Speed | 18–24 h after isolate | 18–24 h after isolate | Hours (direct specimen possible) | Days + bioinformatics |
| Coverage | Drugs tested | Drugs tested | Known markers only | Comprehensive |
Organism identification
MALDI-TOF is shown as a future/optional technology and is not currently an active ID Labs service.
| Feature | Biochemical identification | MALDI-TOF MS (future) | Molecular identification |
|---|---|---|---|
| Time after isolate | Hours–overnight | Minutes | Hours |
| Principle | Metabolic reactions | Protein mass fingerprint | DNA sequence/signature |
| AST included | No | No | No (markers only) |