Evaluation of Internal Quality Control in ELISA Performance for HIV, HCV, and HBV Screening at a Tertiary Care Hospital Blood Centre: A Prospective Observational Study (Code-T0365)

Introduction: Blood transfusion, while lifesaving, carries a risk of transmitting infectious 
agents. Enzyme-linked immunosorbent assay (ELISA) is the gold standard for screening 
transfusion-transmitted infections (TTIs) such as HIV, HCV, and HBV due to its high 
sensitivity and specificity. Ensuring the accuracy and reliability of ELISA results is crucial 
for maintaining transfusion safety, necessitating the implementation of a robust internal 
quality control (IQC) program. 
Aims and Objectives 
 To detect the random and systematic errors by using “in-house” control samples. 
 To check the reliability of using in-house controls by comparing with the standard kit 
controls. 
Objectives: 
 To increase the sensitivity of the Quality Control of the TTI laboratory by using the 
in-house controls taken from borderline positive samples. 
Methods: This prospective observational study was conducted at the Department of 
Immuno-Hematology and Blood Transfusion, Nizam’s Institute of Medical Sciences. A total 
of 540 donor samples for each infection were tested using ELISA. In-house IQC samples 
were prepared from borderline reactive sera and analyzed daily alongside commercial 
controls. Levey-Jennings (LJ) charts and Westgard rules were applied for performance 
monitoring. 
Results: IQC samples demonstrated reliable performance in detecting systematic and random 
errors. LJ charts effectively tracked assay variability, and Westgard rules helped identify 
deviations. In-house controls exhibited comparable reliability to commercial kit controls, 
proving to be cost-effective and flexible. 
Conclusion: Implementing an IQC program using in-house controls enhances ELISA 
reliability, ensuring transfusion safety. This approach provides an efficient, cost-effective 
strategy for continuous quality monitoring in blood banks. 
Keywords: Internal quality control, ELISA, HIV, HCV, HBV, transfusion-transmitted 
infections, Levey-Jennings chart.