# Added Value of Nucleic Acid Testing in Blood Banks: A 15-Year Retrospective Study from India

## TL;DR

This study shows that nucleic acid testing (NAT) in blood banks improves safety by detecting more viral infections than traditional tests in India.

## Contribution

The study provides 15 years of real-world data on NAT's added value in blood safety in India.

## Key findings

- NAT detected 205 additional TTI cases missed by serology, mostly for HBV.
- Seropositivity was highest for HBV, followed by HCV and HIV.
- The overall NAT yield rate was 1:1005, with HBV at 1:1262.

## Abstract

Background

Viral transfusion-transmissible infections (TTIs), hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) pose a major risk to blood safety in India, where most blood banks rely on serology alone for TTI screening. Our blood bank at Max Healthcare, New Delhi, India, has used nucleic acid testing (NAT) alongside serology for TTI screening since 2010.

Objectives

The aim of this study was to evaluate 15 years of real-world blood bank data to evaluate the impact of NAT alongside serology in improving TTI detection and transfusion safety.

Methods

This single-centre retrospective observational study analysed blood donor, serology, and NAT data from 211,555 donations between January 2010 and December 2024. All donations underwent chemiluminescence immunoassay (CLIA)-based serology for TTI detection. All seronegative samples were subject to NAT on the Cobas MPX polymerase chain reaction (PCR)-based minipool NAT (Roche, Basel, Switzerland). Seropositive donations and NAT-reactive donations were discarded.

Results

A total of 2,04,609 (96.72%) were replacement donations. A total of 3,333 (1.58%) donations were seropositive for viral TTIs, and most of these were from replacement donors (N=3,289; 98.68%). Seropositivity was highest for HBV (N=1,460; 43.78%), followed by HCV (N=1,213; 36.39%) and HIV (N=660; 19.8%). NAT detected 205 additional TTI cases missed by serology; most (N=164; 79.76%) were HBV NAT yields, followed by HCV (N=35; 16.83%) and HIV (N=7; 3.41%). There was one case of HBV-HCV co-infection. The overall NAT yield rate was 1:1005, and the HBV NAT yield rate was 1:1262.

Conclusion

NAT enhances blood safety by detecting infections missed by serology, supporting the need for mandatory nationwide implementation despite cost and infrastructure challenges.