Which of the following techniques are used for early diagnosis of diseases?
(A). Urine analysis
(B). PCR
(C). ELISA
(D). Recombinant DNA technology (RDT)
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (B), (C) and (D) only
Early diagnosis means finding a disease while the pathogen is still very few in number, before the symptoms appear. Treatment then works best.
(A). Urine analysis — Incorrect. Urine and serum analysis are conventional methods of diagnosis. They can find a disease only after it has changed the body enough to show up, so they cannot detect it early.
(B). PCR — Correct. PCR makes many copies of the DNA or RNA of a pathogen. Even a very small number of bacteria or viruses can then be detected, as is done to find HIV in suspected AIDS patients.
(C). ELISA — Correct. ELISA works on the antigen-antibody reaction. It detects the antigens of a pathogen, or the antibodies the body makes against it, while the infection is still at an early stage.
(D). Recombinant DNA technology (RDT) — Correct. rDNA technology gives probes, labelled pieces of DNA or RNA, that bind to their complementary DNA in a sample. A probe can show a mutated gene or the DNA of a pathogen early.
Note: A similar question was also asked in CUET (UG) 2025 on 02-06-2025 (Slot 2).
NCERT Extract:
Molecular Diagnosis – “… You know that for effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important. Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis.”