P-2189. Performance of Dried Blood Spots Cards for Serologic Detection of HPV16 Antibodies in Oropharyngeal Squamous Cell Carcinoma Patients

TL;DR

Dried blood spot cards accurately detect HPV16 antibodies in cancer patients, offering a low-cost alternative for areas with limited resources.

Contribution

Demonstrates the feasibility of using dried blood spots for HPV16 antibody detection in oropharyngeal cancer patients.

Findings

DBS cards showed strong correlation with serum for HPV16 E6 antibodies (R² = 0.68) and high sensitivity (90%) and specificity (100%).

Specificity was consistently 100% across all HPV16 markers, though sensitivity varied from 0% to 100%.

DBS cards are a scalable and cost-effective alternative for serologic testing in underserved regions.

Abstract

Antibodies against the human papillomavirus type 16 (HPV16) E6 oncoprotein are a promising biomarker for the early detection of HPV-driven oropharyngeal squamous cell carcinoma (HPV+OPSCC). However, standard serologic testing poses logistical barriers in underserved regions where HPV+OPSCC incidence is high. Dried blood spot (DBS) cards offer a low-resource alternative, but have not been evaluated for HPV antibody detection.

25 OPSCC patients were recruited from the University of Kentucky and provided paired serum (venipuncture) and DBS (finger prick) samples. HPV16 antibodies (L1, E1, E2, E4, E6, E7) were measured using multiplex serology; levels were quantified as median fluorescence intensity (MFI) and dichotomized using established cutoffs. Correlation between serum (gold standard) and DBS MFI values was assessed using linear regression and Bland-Altman plots. Sensitivity, specificity, and Cohen’s kappa were calculated to evaluate agreement.

Mean MFI levels were lower in DBS than serum, but values were strongly correlated with R² ranging from 0.54 to 0.93. The R-squared for HPV16 E6 antibodies was 0.68. Among the 20 HPV16 E6 seropositive participants (serum), 18 were seropositive on DBS (Sensitivity: 90%); all five HPV16 E6 seronegative participants (serum) also tested seronegative on DBS (Specificity: 100%; kappa: 0.787). Specificity was 100% across all markers, while sensitivity varied from 0% (HPV16 L1) to 100% (HPV16 E2).

DBS cards are an accurate, inexpensive, and scalable alternative to serum-based testing for HPV16 E6 antibodies, particularly in medically underserved regions. Further studies are needed to validate these findings and support broader implementation.

All Authors: No reported disclosures