The NSW coroner says the death of a 13-year-old serves as a reminder to clinicians not to ignore vital signs.

Luca Thomas Raso, 13, died on February 27, 2017.

An inquest into his death by Coroner Teresa O'Sullivan has found the boy was twice been misdiagnosed with gastroenteritis.

He died from peritonitis, complicated by gangrenous appendicitis.

The inquest was told no pathology tests were ordered when the boy presented to hospital, and that the GP, Dr Pavlo (Paul) Bilokoptyov, categorically ruled out appendicitis.

Luca died in an ambulance after a week of illness.

The inquest heard that the death was preventable, and the matter should be referred to the Royal Australian College of General Practitioners.

Coroner Teresa O'Sullivan said it was not her role to apportion blame.

“Rather than criticise Dr Bilokoptyov — who I note has been reviewed by the Medical Council NSW, with no further action taken — it is far more productive in my view to remind the medical profession that … the devil is in the detail,” she said.

“To search for the details requires probing and scrutinising the patient's presenting history and conducting a thorough and complete examination to establish the provisional diagnosis but includes eliminating the differential diagnosis, in particular when the differential diagnosis — if left untreated — can present as a medical emergency and [be] fatal.”

The boy’s mother, Michelle Degenhardt, said the case must change the way vital signs are checked and documented, though nothing will bring her child back.

“If the doctor had checked Luca's vital signs it would have made the difference between life and death,” she said.

“I believe it should be mandatory for all children to have their vital signs taken. Kids can't explain what's happened to them, doctors need to find the time to do that.

“It's too late after somebody dies.”