Ilse van Loggereneerg was frantically driving her 13-year-old son from Matamata to Waikato Hospital on Saturday night when police stopped her car.

They wanted to know why she was travelling with her hazard lights flashing. She explained she was racing Aydan, who has severe type 1 diabetes, to hospital.

He'd been feeling unwell and decided to test his blood sugar levels with a home glucose test machine.

REXINE HAWES/SUPPLIED Rudolf van Loggereneerg with his son Aydan.

When the ketones were so high they didn't give a clear measure, van Loggereneerg knew something was wrong.

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"So I phoned the after-hours number at the hospital and they said to bring him in immediately."

Ketones are an acid the body produces when there is not enough insulin. When they reach dangerous levels, the body goes into ketoacidosis - a life-threatening condition that leads to coma and possibly death.

Aydan's body was aching and he'd started to tremble.

"I was petrified. He's been in a ketoacidosis before and ended up in intensive care."

Aydan refused to let her call an ambulance. With no time to argue, she bundled him into the car.

"At that point, it made sense to get him to hospital as quickly as possible. You're trying to keep the child awake, concentrating on the road and the driving."

Not far from the Piarere intersection, van Loggereneerg spotted flashing lights in her rear vision mirror.

"One of the officers asked me what was wrong and I told him I just had to get my son to the hospital as fast as possible."

The constables didn't hesitate, she says. They told her "no worries", scooped Aydan from the front passenger seat and put him into the patrol car.

Under lights and sirens, they got the teenager to hospital 30 minutes faster than van Loggereneerg legally could.

They took him into ED and explained to the doctors.

By the time van Loggereneerg arrived, both constables were gone.

"Being a mother with a child with a chronic illness that could take him away any second, I wanted to thank them personally. We can't thank them enough.

"Their actions definitely made a difference."

Aydan spent the night in Waikato Hospital where he was fed insulin and given a treatment plan to restore normal glucose levels.

He returned home on Sunday afternoon to tell his father about the "highlight of the trip".

"It's just been a fantastic experience and we've only been in the country for a year," his mum said.

Escalating crime pushed the South African family to emigrate a year ago.

"For us it was an absolute experience and fantastic to see that the officers took it upon themselves to get him to hospital as quickly as possible."