Slack parents failed to take their children to more than 20,000 outpatient appointments at Perth Children’s Hospital last year, wasting more than $7 million in staffing and resources.

Figures show that children booked for ear, nose and throat specialist appointments had the most no-shows.

Overall, almost one in 10 booked appointments at the outpatient clinics at PCH — and Princess Margaret Hospital before it closed — were not kept.

The figures do not include cases where families cancelled because a child was sick or they could not make the appointment.

At last count, more than 10,000 children were waiting for outpatient clinic appointments at PCH.

On average, they were waiting almost eight months for their first appointment.

The hospital said appointments cost an average $345 each, and if patients failed to turn up without notice it was too late to divert staff and resources to other needy cases.

Aresh Anwar, chief executive of the Child and Adolescent Health Service, said more than 215,000 outpatient appointments were booked at PMH and PCH last year.

“Across all speciality clinical areas, 9 per cent of booked appointments were not used — that is the patient did not attend — a total over the year of more than 20,000 unused appointments,” he said.

“In the busiest specialties the highest did-not-attend rate was 16.5 per cent in the ear, nose and throat clinics, with more than 1600 missed appointments last year.”

Dr Anwar said reasons why a child might miss an appointment included not needing it any more, transport issues or families moving and not updating their address.

Booking details were mailed to families about four weeks before the scheduled appointment, with a follow-up reminder text message 48 hours before the appointment.

He said the Health Department was working on ways to notify patients of their appointments via smartphones.

“Families should contact us as soon as possible if they are unable to attend the appointment, as this means we are able to see other children on the waitlist sooner,” Dr Anwar said.

“We are seeing an average of almost one in 10 of our outpatient appointments at PCH wasted because families fail to attend.

“This puts unnecessary pressure on the hospital.”