Critically examine the limitations of ELISA-based blood screening in India and evaluate how adoption of Nucleic Acid Testing (NAT) can address the residual risk of transfusion-transmitted infections. What governance model would best suit India's federal structure?

Q. Critically examine the limitations of ELISA-based blood screening in India and evaluate how adoption of Nucleic Acid Testing (NAT) can address the residual risk of transfusion-transmitted infections. What governance model would best suit India's federal structure? (15 marks, 250-350 words)

Safe blood is integral to the right to life under Article 21, yet most Indian blood banks still screen only by ELISA. The Supreme Court, examining a plea for mandatory NAT, flagged whether resource-constrained States could fund it [1] — framing this as a science-versus-fiscal-capacity question.

Limitations of ELISA-based screening - ELISA detects antibodies/antigens, not viral genetic material, so recently infected donors test false-negative during the serological window period [4]. - Residual risk is measurable: a 15-year study of 2.1 lakh donations found 205 infections missed by serology (about 1 per 1,005 donations), of which 79.76% were HBV [2]. - The burden falls hardest on repeat-transfusion patients — thalassaemia, haemophilia and cancer cases — converting a rare per-unit risk into a cumulative one.

Evaluating NAT's contribution - NAT directly amplifies viral RNA/DNA, shrinking the window from weeks to days and cutting residual risk sharply [4]. - Madhya Pradesh's centralised programme found 943 NAT-reactive units among 1.58 lakh seronegative samples (1 in 168) that serology cleared [3]. - Limits persist: individual-donation NAT is capital-intensive, needs trained manpower and assured volumes; pooled NAT dilutes sensitivity; and NAT supplements, not replaces, serology. - Verdict: the safety gain is proven, but cost-effectiveness collapses at low-throughput district banks — so universal uniform mandating is premature.

A workable governance model Public health is a State subject (Entry 6), but blood products are centrally regulated through the Drugs and Cosmetics Act, 1940 and CDSCO — permitting standard-setting without coercion. The optimal design is a hub-and-spoke centralised NAT network on the Madhya Pradesh public-private partnership template [3], with Centre-funded capital costs and State-run operations, phased from high-volume centres outward.

Blood safety is therefore best advanced not by an unfunded judicial mandate but by cooperative federalism — CDSCO setting the norm, regional hubs delivering economies of scale, and a revised National Blood Policy anchoring the transition, moving India toward SDG-3 and a genuinely enforceable Article 21 guarantee.

(~320 words)

Sources: 1. SC to look into feasibility of NAT for blood transfusion — The Hindu, 3 March 2026 — Supreme Court hearing, cost-feasibility and State fiscal capacity concerns 2. Added Value of Nucleic Acid Testing in Blood Banks: A 15-Year Retrospective Study from India — PMC — 205 serology-missed infections, 1 per 1,005 donations, HBV 79.76% share 3. Blood Safety: The Madhya Pradesh Centralized Nucleic Acid Testing (NAT) Model for Blood Donor Screening — PMC — 943 NAT-reactive among 1,58,493 seronegative samples; hub-and-spoke PPP model 4. Blood safety and availability — World Health Organization fact sheet — window period limits of serological screening; NAT detection of window-period infections