Field evaluation of two commercial feline immunodeficiency virus antibody detection point-of-care kits in domestic cats.

Abstract

BACKGROUND: Timely diagnosis of feline immunodeficiency virus (FIV) is essential for informed clinical decision-making, particularly when screening cats before admission into multi-cat environments or assessing blood donor candidates. Point-of-care (PoC) antibody detection kits play a central role in these settings, but their clinical utility relies on independent evaluations under field conditions. This study aimed to assess the diagnostic performance of two commercially available PoC kits for which independent evaluation data are lacking. METHODS: A total of 116 archived serum samples from a previous FIV survey in Egypt were included, comprising 62 FIV-infected and 54 FIV-non-infected cats. Infection status had been determined previously using a diagnostic panel including two PoC kits with demonstrated high accuracy and PCR. Sequencing of available positive PCR samples revealed the sole presence of a novel subtype “X-EGY.” All samples were tested in parallel using the two kits under evaluation and independently interpreted by three observers blinded to infection status. Diagnostic accuracy, sensitivity, and specificity were calculated. Positive predictive value (PPV) and negative predictive value (NPV) were estimated using the calculated kit sensitivity and specificity, and the local FIV prevalence. Additionally, inter-kit agreement was assessed using Cohen’s kappa statistic. RESULTS: Both kits demonstrated 100% diagnostic specificity in the sample set used. However, substantial differences were observed in diagnostic sensitivity (98.39% versus 61.29%) and test line intensity among concordant positive results. In the context of high local FIV prevalence previously reported in Egypt (31.6%), both kits showed 100% PPV, whereas NPV differed markedly (99.26% versus 84.83%), reflecting differences in diagnostic sensitivity. The overall agreement between the kits was moderate (kappa = 0.58). CONCLUSION: This study demonstrates marked disparities in the diagnostic performance of two commercially available FIV PoC kits under identical local conditions. High-prevalence settings like Egypt require PoC kits with high sensitivity to ensure a reliable NPV and prevent missed infections. Additionally, the circulation of a divergent subtype among Egyptian cats can also impair detection, further necessitating the use of high-sensitivity kits. Together, these factors underscore the urgent need for evaluation of PoC kits under local epidemiological and virological conditions to inform evidence-based kit selection in practice. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-026-05416-9.