An overview of the principles, significance, and applications of molecular diagnostics in healthcare, including the detection of genetic variations, infectious diseases, and cancer.
Introduction to Molecular Diagnostics
Key concepts, workflow, technologies, and clinical applications
| Aspect | Description |
|---|---|
| Definition | Use of nucleic acid–based techniques to detect, quantify, or characterize DNA, RNA, or related molecules in a patient sample. |
| Goal | Provide rapid, precise, and often quantitative information about genetic alterations, infectious agents, or biomarkers that guide diagnosis, prognosis, and therapy. |
| Scope | - Infectious disease testing (viral, bacterial, fungal) - Genetic disease screening (carrier, prenatal, newborn) - Oncology (mutation profiling, minimal residual disease) - Pharmacogenomics (drug‑response prediction) |
Pre‑analytical Phase
Analytical Phase
Post‑analytical Phase
| Technology | Principle | Typical Turn‑around | Main Uses |
|---|---|---|---|
| Conventional PCR | Thermal cycling amplifies DNA | 2–4 h | Pathogen detection, genotyping |
| Real‑time qPCR (RT‑qPCR) | Fluorescent probes monitor amplification in real time | 1–2 h | Viral load, gene expression |
| Isothermal Amplification (LAMP, RPA) | Amplification at a single temperature | < 30 min | Point‑of‑care, low‑resource settings |
| DNA Microarrays | Hybridization of labeled targets to thousands of probes | 4–6 h | SNP panels, pathogen panels |
| Next‑Generation Sequencing (NGS) | Massive parallel sequencing of millions of fragments | 1–3 days (clinical panels) | Comprehensive mutation profiling, metagenomics |
| Digital PCR (dPCR) | Partitioned reactions enable absolute quantification | 2–4 h | Low‑frequency mutation detection, copy‑number analysis |
| CRISPR‑based Diagnostics (e.g., SHERLOCK, DETECTR) | Cas enzymes cleave reporter upon target binding | < 1 h | Rapid viral detection, field testing |