Judge sets ‘absolute confidence’ as screening threshold
Morrissey decision sets legal precedent for negligence in screening programmes
Ruth Morrissey outside the Four Courts: this is the first CervicalCheck case in which a court has heard the evidence and delivered a ruling. Photograph: Dave Meehan
The decision by Mr Justice Kevin Cross has set a legal precedent for how negligence should be assessed in medical screening programmes – programmes that necessarily involve uncertainty.
The threshold that has been set for giving a test slide, containing cells taken to be screened, the all-clear has been set by the judge at “absolute confidence”.
The ruling has implications for all types of screening programmes and not just those for cervical cancer.
If the ruling makes it too easy for laboratories to be found guilty of negligence, screening programmes could, in a worst-case scenario, be made prohibitively, or restrictively, expensive.
No doubt this is something Mr Justice Cross was well aware of as he pencilled his 86-page ruling.
A screening programme is not a diagnostic programme. It is a way of looking for signs that there are reasons to be concerned. Because it is uncertain in its findings, audits (or reviews) are carried out when a patient who has been told their smear is clear, is subsequently diagnosed as having cancer.
The smear slide is re-examined, to see if there were signs that were missed. This auditing process is designed to improve the system, for everyone’s benefit.
In 2009 Ruth Morrissey had a smear sample sent for screening to the laboratories of Quest Diagnostic Incorporated, in the US. She was given the all-clear.
A smear taken in 2012 was sent to the Dublin laboratory of MedLab Pathology Ltd, which is owned by an Australian multinational. Again, she was given the all-clear.
In 2014 Ms Morrissey was diagnosed as having cervical cancer. She received treatment, which appeared to be successful.
Meanwhile, unknown to Ms Morrissey, audits were conducted of her 2009 and 2012 samples. Reviews conducted by Quest and MedLab on the respective samples concluded that they had been inaccurately read.
The review by MedLab also decided that its sample was “scanty”, meaning there was a “scanty” number of cells on which to base the judgment call.
It is important to note that Ms Morrissey had already, at this stage, been diagnosed with cancer, and had received treatment.
However, in February 2018 she was told her cancer had returned. The prognosis for her is about two years.
Mr Justice Cross ruled that the screener in 2009 should have spotted “clear peculiarities” that appeared in the Quest sample. He believed the US screeners were using their professional skill and judgment and “recording what they believed as a matter of probability was the case”. He found that this decision constituted negligence.
In the case of the 2012 MedLab sample, the judge decided there were abnormalities to be seen on the slide, but that the screener could not be faulted for failing to see them, given their nature.
However, the screener should have noted that the sample was inadequate, in terms of having the required number of cells, and it was negligent of the screener not to seek a better sample. Again “absolute confidence” was the test that should have been applied.
MedLab has disputed the judge’s finding in relation to the adequacy of the sample and has said it intends to appeal.
The people who actually conducted the screening were not called by the laboratories to give evidence. Mr Justice Cross found this “unsatisfactory”.
In assessing the issue of negligence, he cited an English case in which it was stated that a screener examining a sample should not give the all-clear unless the screener had “absolute confidence” that it was clear.
An expert who gave evidence on behalf of Quest said he was unhappy as a scientist with the words “absolute confidence”.
The US experts who gave evidence to the trial were “not entirely happy with the ‘absolute confidence’ test, preferring instead to rely upon the skill and judgment of the cytotechnologist in relation to their opinion as to what was on the slide,” the judge noted.
“I hold that ‘absolute confidence’ is the screener’s practical duty in relation to their analysis of what is on the slide”, the judge said.