Clinical Evaluation of Plasma Separation Cards as a Tool to Collect, Store, and Test Blood Samples for Hepatitis B and C Serological Markers

Community-based screening enhances hepatitis B virus linkage to care among West African migrants in Spain

BACKGROUND

Chronic infection with HBV is responsible for >50% of all hepatocellular cancer cases globally and disproportionately affects sub-Saharan African (sSA) countries. Migration from these countries to Europe has increased substantially in recent years, posing unique challenges to health systems. The aim of this study was to carry out a community-based intervention to increase HBV screening, vaccination, and linkage to care among sSA migrants in Catalonia, Spain.

METHODS

This was a prospective cohort study. Participants ≥18 years were offered community-based HBV screening between 20/11/20 and 21/01/22. Rapid HBV testing and blood sample collection utilizing plasma separation cards were carried out and linkage to care was offered to all participants. HBV vaccination and post-test counseling were performed at a second visit in the community. The main outcome was the odds of those with current HBV infection being successfully linked to hepatology. Rates of completing the care cascade of this model were analyzed.

RESULTS

In the present study, 444 people undergo screening, with 50.6% of participants showing evidence of past or current HBV infection, including an HBsAg prevalence of 9.2%. Migrants with current HBV infection exhibit 5.2 times higher odds of successful linkage to care compared to those in need of post-test counseling or vaccination. The study achieves a successful linkage to care rate of 72% for all participants, with specialist appointments arranged within 15.5 days.

CONCLUSIONS

This community-based HBV screening program provides evidence of a successful model for identifying and providing care, including vaccination, to west African migrants at high risk of HBV infection who may otherwise not engage in care.

Prospective Laboratory Evaluation of the cobas Plasma Separation Card for HIV and Treponema pallidum Antibody Analysis

BACKGROUND

The cobas Plasma Separation Card (PSC; Roche Diagnostics) was developed for HIV viral load testing. This study evaluates the performance of HIV and Treponema pallidum (Tp) antibody (Ab) detection on PSCs as an alternative to dried blood spots (DBSs).

METHODS

EDTA whole blood samples were collected from HIV-positive (n = 100), HIV-negative (n = 50), Tp-positive (n = 100), and Tp-negative patients (n = 50) and spotted on DBS and PSC. Antibody detection performance was evaluated for HIV Ab using the Genscreen ULTRA HIV Ag-Ab test (Bio-Rad) and for Tp Ab using the Syphilis Total Ab test (Bio-Rad). Plasma was used as a reference specimen.

RESULTS

Receiver operating characteristic curve analysis for DBS and PSC generated areas under the curve (AUC + 95% confidence interval) of 0.985 (0.960-1.000) and 0.987 (0.973-1.000) for HIV Ab and 1.000 (1.000-1.000) and 0.996 (0.983-1.000) for Tp Ab, respectively. Receiver operating characteristic areas under the curve were not significantly different between DBS and PSC for HIV or TP Ab. At selected cutoff values rendering at least 99% sensitivity for HIV Ab detection, the specificity was 96% on DBS and 68% on PSC. For Tp Ab detection at 90% sensitivity, 100% specificity is reached on both DBS and PSC (exceeding the required 95%). However, the median quantitative HIV and Tp Ab signal of positive samples significantly decreased in PSC compared with DBS and plasma.

CONCLUSIONS

Although receiver operating characteristic analysis does not seem to indicate significant differences in performance between DBS and PSC, the significant reduction in quantitative Ab detection signal dictates card composition optimization before its use for HIV and Tp Ab detection can be advised.