Ads for three prenatal genetic test firms banned for using misleading statistics
Ads for three prenatal testing services for genetic conditions including Down’s syndrome have been banned for using misleading statistics about their accuracy.
The Advertising Standards Authority (ASA) investigated claims for the non-invasive prenatal tests (NIPTs) offered by My Baby Company, The Birth Company and Ultrasound Direct, finding that all three exaggerated the accuracy with which the treatment could detect whether a foetus would have specified genetic conditions.
The website mybabycompany.co.uk, seen in April 2019, promoted its test under the heading “Sensitivity”, stating that it was reliable even at a low fetal fraction – the term given to the proportion of DNA belonging to the placenta found in the mother’s blood.
The firm provided a response from its test provider, which said the test had a false positive rate of less than 0.1% and was able to identify Down’s syndrome, Edwards’ syndrome and Patau’s syndrome in more than 99% of cases.
The supplier further claimed that its test had a Positive Predictive Value (PPV) which ranged from 59% to 99% for the different conditions, meaning that out of all the foetuses with “positive” results, 59% to 99% would ultimately have the relevant condition.
The ASA said consumers were likely to understand the initial 99% claim to mean that there was a 99% chance that a foetus would ultimately have those conditions following a “positive” result.
However it noted that any positive result would require further invasive tests to confirm, while the PPV results were based on a study that involved a selected sample of women who already had a high chance of having a foetus with a genetic anomaly.
The Birth Company, which listed the figures “99%” for Down’s syndrome and “93.8%” for Patau’s syndrome, said data on its website related to the detection rate and the false positive rate of its Harmony Test.
It said the Harmony Test had a Positive Predictive Value of 80.9%, which represented the proportion of patients given a high probability result who go on to have the condition confirmed in the foetus, but explained that this was not included in the ad as it varied from patient to patient.
The ASA said: “We understood that a systematic review of the performance of non-invasive prenatal testing in general found that it had a Positive Predictive Value (PPV) of 82% for Down’s syndrome, 37% for Edwards’ syndrome and 49% for Patau’s syndrome, meaning out of all the foetuses with ‘positive’ results, 82% would ultimately have Down’s syndrome, as opposed to the 99% detection rate figure that consumers would understand from the ad.”
Ultrasound Direct said its test detected more than 99% of Down’s syndrome cases, and provided a report which showed that it identified 107 out of 108 cases.
The ASA said consumers would interpret the claim to mean that there was a 99% chance that a foetus would ultimately have Down’s syndrome following a positive result.
However it found that the figure did not give any insight into the proportion of positive results where the foetus would ultimately not have Down’s syndrome.
In relation to all three firms, the ASA said: “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.”
Ultrasound Direct said: “It has never been the intent of Ultrasound Direct to mislead customers or provide false promises of the effectiveness of any of its services.
“It was our belief the information, provided by manufacturers and suppliers of the NIPT test, was truthful and gave potential customers the full facts they required to make an informed decision.”
My Baby Company said: “The accuracy claims on our website were taken directly from the test provider’s marketing material. Therefore, they are their claims, not the claims of My Baby Company.
“My Baby Company is working with our test providers to incorporate the requests made by the ASA into their marketing material so that we can update our website in the manner requested.”