ionainstitute
Whether you are pro-life or pro-choice you will want couples to receive accurate information about the health of the baby they are expecting. A terrible case that occurred in Holles Street earlier this year shows that some of these tests are not as accurate as advertised. In this instance, a chromosomal abnormality was detected where there was none.
So-called NIPTs (Non-Invasive Prenatal Tests) are used to detect foetal abnormalities such as Down Syndrome, Edwards Syndrome or Patau Syndrome (trisomy 21, 18 and 13 respectively).
Last month, the UK Advertising Standard Authority (ASA) ruled that a number of ads for some of those tests run by clinics in the UK were misleading as they claimed to be accurate in about 99% of cases. This is commonly understood to mean that when there is a ‘positive’ result, i.e. when the test indicates that a certain condition is highly likely to be present, this result is correct in about 99 out of 100 tests.
But this misleading, as the APA pointed out. In more cases than the average person might be led to believe, the result is wrong.
The ASA ruling found that when false positives are taken into consideration, a much smaller proportion of foetuses are found to have an abnormality. For instance, in the general population prenatal tests were correctly predictive at 81.6 pc for Down Syndrome, 37 pc for Edwards Syndrome and 49 pc for Patau Syndrome. (These are called Positive Predictive Values).
An 81.6 pc accuracy rate for Down Syndrome may sound high, but it still means that in almost 20 pc of cases when a couple do not wait for a further test, a healthy baby will be aborted.
As we have seen, the situation is much worse for Edwards Syndrome. Three out of five babies are healthy even if the screening test says that they had that condition.
The Advertising Standard Authority ruled in respect of one ad: “We considered that the detection rates in the ad were therefore likely to mislead consumers regarding the accuracy of a positive NIPT result. Because consumers were likely to understand from the ad that the detection rate signified the likelihood that the foetus would have the relevant condition in the event of a ‘positive result’, when that was not the case, we concluded that the ad was misleading.”
The APA told the companies to “avoid using the detection rate figure or alternatively, if referencing the detection rate, to quote robust Positive Predictive Values (based on adequate evidence) alongside an accompanying explanation of both figures.”
It reached the same ruling for two other ads, namely that they misleadingly exaggerated the accuracy of the test.
We had a look at similar ads for NIPT offered by clinics attached to the three maternity hospitals in Dublin.
Here there are from the Rotunda Private, Coombe Fetal Medicine and the Merrion Foetal Clinic at the National Maternity Hospital.
Crucially, none of them mention Positive Predictive Values which gives the best indication of how accurate these tests are.
What would the Advertising Standard Authority in the UK think of these ads? What would our advertising authority think, if asked? Does our Health Minister, Simon Harris have an opinion? Giving couples full information in these cases can be a literal life or death decision. The stakes couldn’t be higher.
