Sandipan Dhar died at Joondalup Health Campus in March, weeks after developing a mild fever following vaccinations.
His parents, Sanjoy and Saraswati Dhar, previously said they asked for a blood test at the hospital but a senior doctor refused to do it.
Private operator Ramsay Health Care, which runs the campus, released an independent review into the hospital's paediatric emergency services on Tuesday.
It identified improvements related to how parents express and escalate concern, and how clinicians respond to these concerns.
The expert panel found care would have been enhanced with clearer two-way communication between clinicians and Sandipan's parents.
The report also identified the need to improve documentation and discharge summaries and processes.
Ramsay Health Care State Manager Shane Kelly said the hospital would implement nine recommendations within its scope.
He noted the review also found Sandipan's clinical care was acceptable and that it was reasonable for staff not to order blood tests during the 21-month-old's first presentation
"The death of Sandipan is a tragedy that has devastated his family and saddened our hospital community," he said.
The review also confirmed Olivia Bakranich-Fowler's missed deadly tiger snake bite diagnosis in May.
The 10-year-old was reportedly suffering from vomiting, blurred vision, and severe pain but doctors told her mother to take her home after misinterpreting a blood test.
Staff at another hospital read the same test and concluded Olivia was likely to have been bitten by a snake before administering anti-venom.
Health Minister Amber-Jade Sanderson said the review highlighted the importance of listening to parents.
"I have always said that parents know their children best," she said.
"I believe the Dhar family when they say they advocated strongly for their child.
"We're working to elevate concerns of parents right across the healthcare system and this is an important recommendation and one that can be used in other healthcare settings across our system."
Mr Dhar previously told the media the coroner had advised that Sandipan died from complications of acute lymphoblastic leukaemia, the most common form of childhood cancer.
When diagnosed and treated early it has a survival rate of about 90 per cent.
Sandipan was taken to Joondalup Health Campus on March 22 and his parents have previously said they spent six hours asking for a blood test but were advised to return home.
His parents took their son back to the hospital two days later after he began coughing and lost his appetite.
The boy's condition deteriorated and he died at the hospital a few hours later.
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