Reasons for rejection of self‐collected samples for cervical screening

To the Editor: Self‐collected vaginal samples are as effective as clinician‐collected cervical samples for detecting underlying cervical intraepithelial neoplasia grade 2 or higher (the target lesion of cervical screening) using polymerase chain reaction‐based oncogenic human papillomavirus DNA assays.1 However, the use of self‐collection within Australia’s cervical screening program is currently restricted to women who are underscreened or never screened (at least 2 years overdue, so 4 years since their last Pap test), aged ≥ 30 years and refuse a clinician‐collected sample. This is because, at the time the current policy was developed, self‐collection was believed to result in a small loss of sensitivity. Accredited laboratories are not permitted to test samples that do not meet these requirements.

VCS Pathology (part of the Australian Centre for the Prevention of Cervical Cancer) was the first laboratory to receive regulatory approval to process self‐collected samples. Here we report the reasons for rejection of samples received between February 2018 and 30 June 2021, which is important given that about one‐third (34%; 2166/6234) of samples received could not be processed (37.4% in 2018; 37.9% in 2019; 34.1% in 2020; 22.8% in 2021). The three most common reasons were that the person was not sufficiently overdue (54.1% of rejected samples; 18.5% of all samples); that the wrong type of collection device was used (17.3% of rejected samples; 5.9% of all samples); or that the person was < 30 years of age (11.2% of rejected samples; 3.8% of all samples). Other reasons included delayed sample receipt (5.2% of rejected samples; 1.8% of all samples), presence of symptoms (3.0% of rejected samples; 1.0% of all samples) and multiple reasons (combination of above factors: 6.6% of rejected samples; 2.3% of all samples) (Box).

The implementation of self‐collection, while known to be highly acceptable to many women who will not accept a speculum examination for screening,1,2 has been problematic in Australia to date.3,4 The eligibility restrictions and strict laboratory requirements have created unintended barriers for practitioners and potential participants, as demonstrated by both the sample rejection rate and low overall numbers compared with the eligible population (< 1%).3 The recently announced mainstreaming of self‐collection, by making it a choice for all screening participants using on‐label tests, should overcome many of these barriers5 and improve program equity and participation. Successful implementation will depend on timely education, communication and change management.

Box – Proportion of 6234 self‐collected samples received that were unable to be processed, by reason and year of receipt (VCS Pathology, February 2018 to the end of June 2021)

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* Incorrect collection device refers to wrong swab type or media. † Other reasons include duplicate samples, and pregnancy (which was initially an exclusion criterion).