Dr. Karin Denton:

The bottom line is that it is very difficult to find out the actual sensitivity of a test. How would that be found out? The only way to get a fairly robust answer is in the context of randomised control trials which are not possible or desirable in this setting. We must examine other markers, things that are based on process. As we mentioned before, there is the question of whether a slide is screened once or twice. If two separate people are screening a slide, then more abnormalities will be detected than if only one person screens it. The US requirement is for only one person to screen the US-derived slides and to do a 10% rescreen. Therefore 90% of its negative slides are only being screened by one person. What was, and still is, being offered to Irish women in those settings is better because they are all having two screens.

We are not able to say that the sensitivity of the test in country A is one thing and in country B is another because it is simply not measurable. What we can say is that the processes being used are as specified and acceptable in the countries in which they are being used.