Differing views have been expressed about the likely impact on screening services of the High Court's judgment in the case of Ruth Morrissey, who is terminally ill with cervical cancer.
The case is the first to have gone all the way to judgment since the CervicalCheck controversy began last year.
In his ruling on Friday, Mr Justice Kevin Cross said laboratory screeners should have “absolute confidence” that there are no abnormalities in a smear slide before they give it the all clear.
He adopted a 1999 ruling of the English Court of Appeal in a case called Penney Palmer & Canon v East Kent Health Authority.
Mr Justice Cross said he agreed with the view expressed in that case that “if there was any doubt in the mind of a screener as to whether the slide was normal, he or she should not classify it as negative.
“A slide should not be classified as negative unless the screeners had ‘absolute confidence’ that it was so.”
Speaking on the This Week programme on RTÉ Radio 1, gynaecological oncologist Donal Brennan expressed concern that the ruling could have a "major impact" on how screening services are delivered in Ireland.
The ruling could lead to “patients being harmed in the long run” because of unnecessary investigations and unnecessary treatments.
If the ruling meant that there were going to be a large number of additional tests because clinicians were unwilling to say that tests were negative, then that could lead to the over-treatment of patients.
He speculated that a woman could end up having an unnecessary hysterectomy because no one providing care to her was willing to declare that tests showed her tissues were normal.
However, Cian O’Carroll, the solicitor who represented Ms Morrissey in her High Court action, said this suggestion was “inappropriate and hysterical”.
He said the judgment simply adopts what has been the law in the UK since 1999.
“The UK’s screening service was described by HSE witnesses as being one of the finest services in the world, and it adheres to this standard,” Mr O’Carroll said. “So why should it not apply in Ireland?” The absolute confidence test was “being ramped up as a bogeyman issue”, he said.
Mr Justice Cross awarded Ms Morrissey and her husband Paul €2.1 million arising out of the negligent reading of CervicalCheck slides in 2009 and 2012.
Prof Brennan said that if the 2009 slide had been accurately read, it was most likely Ms Morrissey would not have developed cancer.
The judge found that the 2009 slide had been negligently read by a US laboratory owned by US multinational Quest Diagnostics.
He found that the 2012 slide had been inaccurately read by Medlab Pathology, of Dublin, which is owned by the Australian multinational Sonic Healthcare. However, he decided that the inaccurate reading was not an instance of negligence.
“Though the 2012 slide contained abnormal and non-negative cells, the nature of these cells was such that the failure to record them as abnormal was not a breach of duty of care.”
However, he said Medlab was negligent because it had not rejected the sample on the grounds that it involved an inadequate number of cells. The company has disputed the finding and is considering an appeal.
The CervicalCheck system was introduced in 2008. In the September 2015 to August 2016 year, 263,481 smears were examined and led to the detection of 8,885 women with precancerous abnormalities, and the diagnosis of invasive cancer in 187 women.
In the period 2000 to 2018, the BreastCheck programme led to the detection of more than 11,000 cancers, according to the Health Service Executive.