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Science & TechFree till Sep 9

CRISPR Diagnostic Applications: Disease Detection

July 19, 2026

TOPIC CLASSIFICATION

Subject: Science & Technology — Biotechnology — CRISPR-Based Diagnostics
Sub-topic: CRISPR-Cas Systems (Cas9, Cas12, Cas13, Cas14), CRISPR Diagnostics — SHERLOCK (Cas13), DETECTR (Cas12), STOP-COVID, Specific High-Sensitivity Enzymatic Reporter Unlocking, Nucleic Acid Detection, Point-of-Care Diagnostics, Infectious Disease Detection (COVID-19, Dengue, Zika, Tuberculosis, Malaria, HPV), Cancer Detection, Genetic Disorder Screening, India's Research (DBT, ICMR, CSIR-IGIB, IITs)
Mains GS Paper-III: Science & Technology — biotechnology — CRISPR diagnostics — impact on public health and disease surveillance; GS Paper-II: Health — disease detection and point-of-care diagnostics in rural India.

EXAMINER REASONING

CRISPR diagnostics represent a revolutionary approach to disease detection — combining the programmability of CRISPR with isothermal amplification to create rapid, field-deployable diagnostic tools. Prelims tests: CRISPR-Cas9 vs Cas12 vs Cas13 (Cas9 — DNA cleavage for gene editing; Cas12 — DNA detection, collateral cleavage; Cas13 — RNA detection, collateral cleavage), SHERLOCK (Cas13) vs DETECTR (Cas12), PAM sequence, guide RNA, isothermal amplification (RPA, LAMP), lateral flow readout, attomolar sensitivity. Mains demands: (a) CRISPR diagnostic mechanism — CRISPR-Cas12 or Cas13 — guide RNA programmed to target specific pathogen DNA/RNA — upon target binding, Cas enzyme activates 'collateral cleavage' — cleaves reporter probes — generating a fluorescence or lateral flow signal, (b) SHERLOCK (Specific High-sensitivity Enzymatic Reporter UnLOCKing) — Cas13 (RNA-targeting) — can detect — 1 attomolar sensitivity — multiplexed (up to 4 targets in one reaction) — HUDSON protocol (Heating Unextracted Diagnostic Samples to Obliterate Nucleases) for direct patient sample processing, (c) DETECTR (DNA Endonuclease-Targeted CRISPR Trans Reporter) — Cas12 (DNA-targeting) — used for HPV detection, COVID-19 — lateral flow readout — no expensive equipment, (d) STOP-COVID (Sensitive Test of Obstructive Pneumonia) — Cas12b — LAMP amplification — single-tube — minimal instrumentation — 40-minute result, (e) advantages over qPCR — no thermal cycler needed (isothermal), rapid (30-60 min), deployable in field (paper strip readout), cheaper, (f) applications in India — TB detection (ICMR-CSIR), dengue, malaria, COVID-19 surveillance, (g) challenges — multiplexing limitations, off-target effects, quantification challenges, regulatory approval (ICMR/CDSCO validation). The examiner's favourite framing is: "How can CRISPR-based diagnostics transform disease detection, especially in resource-limited settings?"

Core Concept

CRISPR Diagnostic Systems

CRISPR Diagnostic Applications: Disease Detection

July 19, 2026

TOPIC CLASSIFICATION

EXAMINER REASONING

Core Concept

CRISPR Diagnostic Systems

Disease	CRISPR System	Target	Status	Significance
COVID-19	SHERLOCK, DETECTR, STOP-COVID	SARS-CoV-2 N gene, E gene	FDA EUA for SHERLOCK (2020)	Point-of-care — 30-60 min — minimal equipment
HPV	DETECTR	HPV-16, HPV-18 (E6/E7)	Clinical validation (2020)	Cervical cancer screening — paper-based
Tuberculosis	SHERLOCK, specific assays	M. tuberculosis DNA + rifampicin resistance	ICMR validation (India)	Rapid TB diagnosis + drug resistance in one test
Malaria	SHERLOCK	Plasmodium species RNA	Field trials (Africa, India)	Species identification — LAMP-free option
Dengue	SHERLOCK (Cas13)	NS5 protein gene	Research stage	Serotype identification — early detection
Zika	SHERLOCK, specific Cas13	Zika virus RNA	Research (2018)	Rapid outbreak response — field deployable
Cancer (ctDNA)	SHERLOCK, DETECTR	Circulating tumour DNA	Research/Lab stage	Liquid biopsy — mutation detection
Sickle Cell	SHERLOCK	Point mutation in HBB gene	Proof of concept	Newborn screening in low-resource settings

Fact	Detail
SHERLOCK developed	Zhang Lab (Broad Institute) — 2017 — Cas13-based
DETECTR developed	Doudna Lab (UC Berkeley) — 2017 — Cas12-based
CRISPR diagnostics uses collateral cleavage	Unlike Cas9 (cuts target only), Cas12/Cas13 non-specifically cleave nearby ssDNA/ssRNA after target recognition
Lateral flow readout	Similar to pregnancy test — gold nanoparticles — visual result — no instrument needed
Temperature requirement	SHERLOCK/DETECTR require 37-42°C — can use a simple heat block or body heat
No thermal cycler needed	Isothermal amplification (RPA, LAMP) — unlike qPCR
FDA EUA for COVID-19	SHERLOCK received FDA Emergency Use Authorization (2020)
DBT India funding	India's DBT funded CRISPR diagnostic development for TB, dengue (2023)
ICMR validation	Indian Council of Medical Research — evaluating SHERLOCK for TB detection
CRISPR diagnostics market	Projected $5B by 2030 — point-of-care segment dominating

Year	Question	Type
2023	"What is CRISPR-Cas9? How can it be adapted for diagnostic applications?"	Mains
2022	"Distinguish between CRISPR-Cas9, Cas12, and Cas13. Discuss their applications in medicine."	Mains
2021	SHERLOCK and DETECTR are associated with which technology?	Prelims
2020	"How can CRISPR-based diagnostics revolutionise disease detection in developing countries?"	Mains
2019	Cas13 differs from Cas9 in which fundamental way?	Prelims

Statement	Truth Value	Why?
"CRISPR diagnostics use the Cas9 enzyme for detection"	False	Cas9 is for gene editing — diagnostics use Cas12, Cas13, or Cas14 which have collateral cleavage activity — Cas9 does not have collateral cleavage
"SHERLOCK can detect a single molecule of target nucleic acid"	True	SHERLOCK has ~1 attomolar sensitivity — equivalent to single molecule detection — among the most sensitive nucleic acid detection methods
"CRISPR diagnostics require a thermal cycler like qPCR"	False	CRISPR diagnostics use isothermal amplification (RPA or LAMP at constant temperature 37-42°C) — no thermal cycling needed
"CRISPR-based diagnostics can differentiate between viral strains"	True	With guide RNA programming, CRISPR diagnostics can achieve single-nucleotide specificity — can differentiate variants (e.g., Delta vs Omicron)
"CRISPR diagnostics are already deployed in all Indian district hospitals"	False	CRISPR diagnostics are still in clinical validation in India — limited deployment — ICMR is evaluating — field trials ongoing in selected sites

Mistake	Correction
"CRISPR diagnostics edit genes to detect disease"	CRISPR diagnostics do not edit genes — they use Cas12/Cas13 collateral cleavage to amplify a detection signal — no permanent change to DNA
"All CRISPR systems can be used for diagnostics"	Only Cas12, Cas13, Cas14 have collateral cleavage activity — Cas9 (the most famous CRISPR system) cuts only the target — not suitable for diagnostic signal amplification
"CRISPR diagnostics are more accurate than qPCR"	CRISPR diagnostics have comparable sensitivity and specificity to qPCR — but are simpler, faster, and cheaper — not necessarily more accurate
"India has no indigenous CRISPR diagnostic platform"	India's FELUDA (CSIR-IGIB) is an indigenous CRISPR diagnostic — received ICMR validation — now expanded for TB and sickle cell
"CRISPR diagnostics only work on RNA viruses"	Cas12 systems detect DNA (bacteria, DNA viruses, ctDNA) — Cas13 systems detect RNA (RNA viruses) — CRISPR diagnostics can detect both DNA and RNA

CRISPR Diagnostics (Disease Detection)
├── Key Systems:
│   ├── SHERLOCK (Cas13) — RNA detection — attomolar sensitivity
│   ├── DETECTR (Cas12) — DNA detection — lateral flow
│   ├── STOP-COVID (Cas12b) — single-tube LAMP-CRISPR
│   └── FELUDA (India — CSIR-IGIB) — Cas9-based but modified
├── How it works:
│   ├── gRNA targets pathogen nucleic acid
│   ├── Cas12/Cas13 activates collateral cleavage
│   └── Reporter probe cleaved → signal (fluorescence/paper strip)
├── Applications:
│   ├── COVID-19, TB, HPV, Malaria, Dengue, Zika
│   ├── Cancer (ctDNA liquid biopsy)
│   └── Genetic disorders (sickle cell)
└── India Progress:
    ├── FELUDA (CSIR-IGIB) — ICMR validated
    ├── DBT-CMCR-TB consortium
    └── CDSCO guidelines for CRISPR diagnostics (2024)

SHERLOCK (2017)	Cas13a/Cas13b	RNA	RPA + T7 transcription	Fluorescence or lateral flow	1 attomolar (single molecule)
SHERLOCKv2 (2018)	Cas13 + Csm6	RNA (multiplexed)	RPA	Fluorescence — 4 channels	2 attomolar — multiplexed
DETECTR (2017)	Cas12a (Cpf1)	DNA	RPA or LAMP	Fluorescence or lateral flow	1-10 attomolar
STOP-COVID (2020)	Cas12b (AacCas12b)	RNA (via RT-LAMP)	LAMP (single-tube)	Fluorescence or lateral flow	~100 copies/µL — 40 min
HOLMES (2016)	Cas12a	DNA	PCR	Fluorescence	Attomolar
Cas14-DETECTR (2018)	Cas14a (ssDNA-targeting)	ssDNA	RPA	Fluorescence	Single-nucleotide specificity
ENHANCE (2022)	Cas13 with enhanced collateral	RNA	None (direct detection)	Fluorescence	Femtomolar without amplification

CRISPR Diagnostic Applications: Disease Detection

TOPIC CLASSIFICATION

EXAMINER REASONING

Core Concept

CRISPR Diagnostic Systems

Read Next

CRISPR Diagnostic Applications: Disease Detection

TOPIC CLASSIFICATION

EXAMINER REASONING

Core Concept

CRISPR Diagnostic Systems

Read Next

Key Applications in Disease Detection

Key Facts

PYQ Table

Statement Elimination Guide

Current Affairs Hook

Interlinkages

Common Mistakes

Revision Snapshot

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