The parents of a girl who died after failings by NHS 111 said they were horrified to learn coroners had already warned about similar shortcomings.
Hannah Royle, 16, died in 2020 after the NHS phone service failed to realise she was seriously ill.
BBC News found concerns had been raised about the call centre triage software in 2019 after three children died.
The NHS said it had learnt lessons from each case, but said it had not established a link between the deaths.
Hannah, who was autistic, had a cardiac arrest as she was driven to East Surrey Hospital by her parents. She had suffered a twisted stomach, but call handlers believed she had gastroenteritis.
A coroner's report said NHS 111 staff failed to consider her "disabilities and inability to verbalise" when using the triage software.
Known as NHS Pathways, the algorithm relies on answers being given over the phone to a set series of questions. The system guides call handlers, who are not medically qualified, to direct patients to other parts of the NHS for further assessment and treatment.
In 2019, three coroners issued reports "to prevent future deaths" after serious abdominal illness in Myla Deviren, Sebastian Hibberd, Alexander Davidson and were missed by NHS 111.
In all cases, coroners raised concerns about the ability of children to understand call handlers' questions or articulate their symptoms.
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Source: BBC News, 24 May 2022