Question

Which one of the following techniques serve the purpose of early diagnosis of diseases?

• A. Stool analysis
• B. Enzyme linked immuno-sorbent assay
• C. Urine analysis
• D. Serum analysis

Hint:

Early Diagnostic Tools:
$\bullet$ Recombinant DNA technology
$\bullet$ Polymerase Chain Reaction (PCR)
$\bullet$ ELISA (Antigen-Antibody interaction)
Conventional methods (Serum, Urine, Stool analysis) only detect infections at later stages.

Answer 1

The Correct Option is B

Concept:
Early detection of disease allows timely medical intervention. Molecular diagnostic tools can detect pathogens even when their concentration is extremely low in the body.

Step 1: Limitations of Conventional Diagnostics:
Conventional diagnostic methods (such as serum analysis, urine analysis, and stool analysis) generally detect diseases only when the pathogen has multiplied significantly and clinical symptoms appear.
Consequently, they do not serve the purpose of early disease diagnosis.

Step 2: Principles of Molecular Diagnostics for Early Detection:
Advanced recombinant DNA technology, Polymerase Chain Reaction (PCR), and Enzyme-Linked Immunosorbent Assay (ELISA) allow early detection of diseases:
- ELISA (Enzyme-Linked Immunosorbent Assay): Based on the principle of antigen-antibody interaction. Infection by pathogens can be detected by identifying very low concentrations of antigens (proteins, glycoproteins) or antibodies synthesized against the pathogen.
- PCR: Amplifies trace amounts of microbial nucleic acids (DNA/RNA) to detect pathogens before symptoms develop.

Step 3: Conclusion:
Among the given options, Enzyme linked immuno-sorbent assay (ELISA) is the recognized molecular tool used for early diagnosis of diseases.