Problems with newborn hearing tests go back as far as 2010, a Ministry of Health investigation has found.
The inquiry was launched towards the end of last year after the ministry discovered irregularities in its national newborn screening programme, which began in 2007.
The investigation found eight screeners, out of a workforce of about 108, had not followed protocol. They had either screened the same ear of a baby twice, screened one ear followed by one of their own ears, or in some cases screened both their own ears instead of the baby's.
Four of the screeners at fault gave explanations including finding the job difficult, laziness, stress and not wanting to put families through the trouble of going through more testing.
The final report, released yesterday, said a small number of babies now aged between 2 and 3 were affected. This does not include babies who were in a special care unit or identified as being at risk of hearing loss, as they are covered by a different screening protocol.
The massive failings affected more than 2000 babies nationwide. If hearing loss goes undetected or is treated late, it may result in delayed speech, language and other development.
It is understood the eight screeners have lost their jobs, while 3500 babies have been offered rescreening.
Irregularities in the screening programme were detected between June and November at six district health boards - Auckland, Lakes, Bay of Plenty, Waitemata, Canterbury and Hutt Valley. Data from other boards was still being reviewed.
The final report includes 21 recommendations, such as a national database for quality monitoring, professional development and support for screeners, and clearer guidance on protocol.
Screeners do not need prior qualifications or experience. They need only to pass a two-week training course run by Canterbury University.
Ministry spokeswoman Marian Mortensen said it was still waiting on information from the Waikato and Hawke's Bay health boards. Until then, it would not be known if the problems were confined to the eight identified screeners.
Associate Health Minister Jo Goodhew said she expected the National Screening Unit would make implementing all of the report's recommendations a priority.
"I am confident that the recommendations of the report, once fully implemented, will strengthen service delivery and NSU oversight so that this situation is very unlikely to arise again in the future, and if it does then it will be able to be discovered and addressed very quickly."
Labour health spokeswoman Maryan Street said it was a real tragedy that the screeners at fault were not picked up earlier. The lessons the ministry should take from the report were that the screening programme needed to be adequately resourced and monitored, with staff who were trained properly and paid decent wages, she said.
DEAF BABY'S HEARING TEST WAS A FAKE, REPORT SHOWS
More than a year after hospital staff failed to detect his daughter's hearing defect, Rawiri Blundell has learnt the "test" was a fake.
Daughter Addison's hearing was never tested at all when she was a newborn, with a Hutt Valley Hospital screener testing her own ears and faking the paperwork.
Addison, now 1, was diagnosed with congenital hearing loss late last year, a condition that should have been picked up routinely within days of her birth.
She cannot hear or speak, and the delay in diagnosis may significantly affect her development.
Revelations that Addison's test was a forgery were contained in the Ministry of Health's report into nationwide failures in the newborn hearing tests published yesterday.
Mr Blundell said the report had left him angry and struggling to understand why anyone would fake results for a newborn baby.
"The behaviour from some of the screeners was simply unacceptable. You can be overworked and underfunded, but they need to have some professional integrity."
While the Hutt Valley District Health Board had been great in helping Addison, he felt it should have told him her test was faked. "It is frustrating that they weren't 100 per cent upfront." Addison was one of 176 babies incorrectly screened at Hutt Hospital. She is the only baby caught up in the testing scandal who is known to have a hearing problem.
She is scheduled to have a state-funded cochlear implant this year, and her parents are trying to raise another $50,000 to cover the expense of a second implant. She will have years of state-funded speech therapy to bring her up to speed with other children.
- The Dominion Post
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