Gota de sangre seca en papel secante como muestra alternativa en el diagnóstico de hepatitis víricas

Abstract

The hepatitis C virus (HCV) represents a significant public health challenge, with a high incidence in vulnerable populations. Despite remarkable advances in the development of direct-acting antivirals that have revolutionized HCV treatment, significant challenges remain, particularly in the area of early detection._x000D_ Early identification of the infection is crucial to preventing transmission and long-term liver complications, such as cirrhosis and hepatocellular carcinoma._x000D_ In this context, this doctoral thesis focuses on evaluating the efficacy and feasibility of dried blood spot (DBS) samples as an innovative diagnostic tool for HCV in hard-to-reach populations. This approach not only addresses logistical issues related to sample collection and transport but also enhances patient acceptance, thereby facilitating the inclusion of those who reject more invasive procedures, such as venipuncture._x000D_ The study includes a rigorous methodological validation, comparing the sensitivity and specificity of dried blood spots with traditional diagnostic techniques using serum and plasma. Results show that dried blood spot testing can be a valid alternative, with a sensitivity of 92.8% and a specificity of 100% for the detection of anti-HCV antibodies, and a sensitivity of 94.9% for HCV RNA detection. These findings are supported by a strong linear correlation and good concordance in comparative analyses._x000D_ At Care and Follow-Up Centers, dried plasma spot cards were implemented as an alternative diagnostic method for HCV in patients who refused conventional venipuncture. This strategy enabled an observational study involving 679 patients, of whom 54 were assessed using these cards. The prevalence of prior HCV exposure was 14.7% in the total study population. Specifically, a prevalence of 9.1% was observed in patients evaluated by venipuncture, whereas the prevalence was significantly higher in those evaluated by fingerstick testing, reaching 79.6%. Similarly, the prevalence of active infection, determined by the presence of HCV RNA, was 3.5% overall, with 27.8% in the fingerstick testing group compared to 1.4% in the venipuncture group._x000D_ Of the 24 patients diagnosed with active HCV infection, 23 were referred to a specialized consultation. Of these, 13 patients effectively attended the consultation. Additionally, 15 patients received treatment, including two who were re-incorporated into clinical follow-up afterward. Among those who completed treatment, a sustained virologic response of 100% was achieved, although it was only evaluated in 12 patients._x000D_ Notably, one case of HCV reinfection was identified after successful treatment in the subgroup of patients screened using fingerstick testing. This finding, along with the fact that individuals who refuse HCV screening via venipuncture present a significantly higher risk of active HCV infection (OR = 26.5), suggests that the subgroup of individuals screened via fingerstick may have an increased risk of HCV infection._x000D_ The inclusion of dried plasma spot cards in the test catalog of the Vall d’Hebron Hospital laboratories not only improved access to HCV screening in high-risk populations but also made a significant contribution to public health efforts toward virus eradication.

Date of Award	15 May 2025
Original language	Spanish
Supervisor	Francisco Rodriguez Frias (Director) & Ariadna Rando Segura (Director)