Boosting HPV Test Accuracy with Optimised Self-Collection

This article investigates how different aspects of vaginal self-collection (SC) workflows affect the performance of HPV testing for cervical cancer screening. As SC gains traction in public health efforts to reach under-screened women, optimising the sample collection and handling process becomes crucial to maintain diagnostic accuracy.

Methodology

The empirical testing utilised Copan FLOQSwab® - a customisable moulded plastic shaft and a tip coated with perpendicular short Nylon® fibres, specifically designed for efficient cell uptake and release. These were used for vaginal SC and to assess the impact of, resuspension volume, swab handling method (swirl-and-toss vs. direct deposit) and media type (lytic vs. fixative).

Three experiments were conducted:

Swirl-and-toss vs. swab deposition into 10 mL BD SurePath™.
Comparison of swab deposition into 3 mL lytic buffer vs. swirl-and-toss into 5 mL PreservCyt.
Comparison of all methods above to clinician-collected (CC) samples.

All samples were analysed using the BD Onclarity™ HPV assay, measuring cell recovery via beta-globin Ct values.

Key Findings

1. Swab Deposition Recovers More Target Material

Depositing the Copan FLOQSwab® directly into media (vs. swirl-and-toss) improved cell recovery by approx. 2-fold, as shown by a 1 Ct reduction.
In another setup, deposition into 3 mL lytic buffer yielded 16 times higher cell recovery than swirl-and-toss into 5 mL PreservCyt.

2. Lower Resuspension Volumes Improve HPV Detection

Reducing the resuspension volume from 10 mL to 3 mL resulted in an additional 2.6 Ct reduction, equating to a 6-fold improvement in target recovery.
This demonstrates that large volumes (designed for cytology, not molecular testing) dilute the analyte and reduce test sensitivity.

3. Direct Deposit in Lytic Media Outperforms Standard CC Methods

Surprisingly, 3 mL FLOQSwab® direct deposit samples outperformed CC samples in 10 mL SurePath by 2 Ct (~4-fold cell recovery advantage).

Meta-analysis Results

A systematic review of 17 studies comparing SC and CC confirmed:

When SC-to-CC resuspension volume ratio was <1.0, relative sensitivity for detecting ≥CIN2 increased to 97%, compared to 92% when the ratio was ≥1.0.
Specificity remained high across the board (94 - 98%).

This confirms that smaller resuspension volumes optimise clinical performance and reinforce the findings of the empirical study.

Why FLOQSwabs® are Ideal for HPV SC

Superior sample elution: FLOQSwabs® have no internal core to trap the sample, allowing rapid adsorption and ensuring fast and complete specimen elution.
Designed for dry transport: Ideal for self-collection kits, especially in community or home-use settings.
Compatible with lytic media: Enhances viral DNA release for highly sensitive HPV detection via PCR.
Validated in high-performance workflows: This study's best-performing setup - FLOQSwab® directly deposited in 3 mL of lytic buffer - sets a new benchmark for self-collection methods.

Summary

This study supports a paradigm shift in cervical screening: SC vaginal samples can match or exceed clinician-collected samples when workflows are optimised. Central to this is the use of Copan FLOQSwabs®, which maximise target recovery and maintain sample integrity. For national screening programmes and diagnostic labs looking to expand reach and maintain accuracy, the message is clear: pairing the right swab with the right media matters.

For more information on Copan Swabs head over to our website, or check out our eShop to put an order in: Sample Collection Devices | Don Whitley Scientific

Paper available on our database:

Vaughan, L., Gary, D., Shah, M., Lewellen, L., Galbraith, L., & Parvu, V. (2024). Variables that impact HPV test accuracy during vaginal self collection workflow for cervical cancer screening. Gynecologic Oncology Reports, 54, 101421.