Dr. Karin Denton:

There are a couple of other questions the Deputy asked that were laboratory specific. On whether the perceived accuracy of the test had an impact on those doing the audit, I heard two aspects of that: the clinicians and the laboratories. Having spoken to people in all the laboratories, I found they were all committed and keen to look again at the slides and learn what they could from them. It interacts with the question of bias, however, because they knew these women had all developed cervical cancer. Different individuals had different approaches to how much they tried to compensate for that bias, but it was not their fault because no one told them what to do. There was no protocol that said one either must or must not compensate for this review bias. The clinicians were all keen to learn what they could from reviewing these slides.

The protocol, such as it was, listed cases that had to go for an external review, and this can be found on pages 86 and 87 of the report. Slides that were identified on internal review as having a significant difference were sent for an external review, which addresses the question the Deputy asked of whether there was another pair of eyes on them. The difference between those internal reviews and the subsequent external reviews is what precipitated CervicalCheck to wonder if there might be an issue with the internal reviews.

I was also asked about how many other countries do an audit like this, and the answer is not many. It is quite unusual. The one we are most familiar is that which runs in England and Wales. It should be recognised that trying to do the audit is a laudable thing, but not every country does it, and most countries have not had this experience. There is not much comparison, therefore, to go on.