Molecular diagnostics - Revolutionizing Healthcare
Medical diagnostics have evolved from the age of urine analysis and microscopy to that of molecular testing. Gone are the days when disease diagnosis was primarily symptom-based and varied with clinician’s experience and perspective. A lack of standardized laboratory techniques often led to inconsistent diagnoses. The emergence of molecular diagnostics has not only helped us achieve accurate and reproducible results but also accelerated diagnosis.
Unlike conventional diagnostic techniques, molecular diagnostics focus on the changes in DNA/RNA sequences associated with disease or abnormality. Although molecular diagnostics have been a part of the diagnostics portfolio for decades (in the form of polymerase chain reaction [PCR] testing), they have advanced rapidly since the COVID-19 pandemic. Automated systems for DNA/RNA extraction, amplification, and labelled detection have further expanded their clinical application. At present, molecular?diagnostics comprise a wide array of laboratory tests for infectious and genetic diseases, while slowly marching towards unexplored areas in cancer diagnosis.
Current Status
Molecular techniques currently applied in clinical scenarios include real-time PCR (quantitative PCR), fluorescence in situ hybridization, use of microarrays, and next-generation sequencing (NGS). These cutting-edge methods expedite diagnosis while offering ultra-high sensitivity.
?Real-time PCR is commonly used to detect pathogenic DNA/RNA in infectious diseases, identify mutations, and monitor drug response in cancer. Moreover, it is rapidly replacing traditional microbiological examination owing to its ability to detect not only infection but also the drug resistance of a pathogen. Real-time PCR can thus contribute to prompt and tailored treatment, lower drug resistance, and patient recovery.
Advanced molecular techniques, including NGS and the use of microarrays, enable cancer prediction and early detection. Cancer screening with NGS has helped reduce cancer-related morbidity and mortality.
Future Prospects
Currently, molecular testing shines the spotlight on disease mechanisms and facilitates personalized patient care.?Its future lies in the much-needed Point-Of-Care Testing (POCT). Nucleic acid amplification techniques (NAATs), such as Polymerase Chain Reaction (PCR), Rolling Circle Amplification (RCA), Loop-Mediated Isothermal Amplification (LAMP), Recombinase Polymerase Amplification (RPA), CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) related amplification, and others are dominating methods employed in molecular diagnostics research.
领英推荐
They each provide distinctively unique features that can offer desirable performance in terms of sensitivity, specificity, simplicity, stability, and cost.?Out of these, RCA, LAMP & RPA employ isothermal amplification overcoming the need of thermal cyclers & thus ideal for developing POCT. Additionally, CRISPR based on highly specific DNA-binding nucleases, has also demonstrated capability for amplified nucleic acid detection with high sensitivity and specificity. A combination of CRISPR proteins and isothermal methods of amplification are currently coming up as the basis of advanced POCT platforms for infectious diseases such as tuberculosis, HIV, and viral hepatitis.
Molecular methods are also expanding their horizons from molecular diagnostics to immunodiagnostics. As a result, we are marching to an era of advanced diagnostics utilizing the principles of molecular diagnostics & immunodiagnostics both. Aptamers (protein binding oligos) screened using robust SELEX (Systemic Evolution of Ligands by Exponential Enrichment) have huge potential to replace antibodies in traditional immunoassays. Aptamers have the potential of not only enabling multiplexing of these assays but also of improving sensitivity tremendously.
Rapidly emerging technological advancements can lead to the creation of molecular POCT devices capable of on-site real time testing allowing for rapid diagnosis and treatment choices. Also, efforts are being made to shift the PCR and other molecular tests from traditional lab set up to chips, popularly being called as lab-on-a-chip. Thus, there is a huge possibility of traditional wet lab to be turning to lab-on-a-chip with the advent of integrated silicon chips loaded with biomolecules, which enable testing analysis of hundreds of genes/proteins in hours.
Appropriate treatment selection is paramount in healthcare, and diagnostic methods serve as the foundation of correct decision making. Therefore, the fast-evolving molecular diagnostics are revolutionizing not only diagnostics but overall healthcare.
?
References