UPLAND (CBSLA.com)  —  Dogs are man’s best friends, and one Upland teen knows his dog is also a virtual lifesaver.

As Upland High senior Luke Van Ginkel kicks off his school’s homecoming game, his dog Astro looks on.

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This is not new. Astro is always looking out for the 18-year-old Van Ginkel.

As KCAL9’s Rachel Kim reports, the teen counts on the dog more than most people count on a pet.

“He’s saved my life countless times,” says Van Ginkel.

The 3-year-old Golden Lab has been by Luke’s side for the past couple of years as his diabetic alert service dog.

Armed with his own student ID, service patches and a nose trained to sniff out danger, Astro lets Luke, a Type 1 diabetic, know every time his blood-sugar level gets too high or too low.

“My body makes a special chemical difference in my scent and saliva in my mouth, and he can smell the difference,” says Van Ginkel of Astro’s special ability.

During Kim’s interview, in fact, Astro alerted Luke by pulling on a stuffed toy the teen keeps on him. So, Luke tested himself and found that his sugar level was really high.

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“I’ve had bad seizures in the past where I’ve gone into a coma because of it and nearly lost my life,” Van Ginkel says.

Astro is always on target.

“I don’t think there’s been a time where he’s been off,” marveled Van Ginkel.

When it’s game time, Astro can still sense Luke’s levels from the sidelines. Occasionally, Astro just wants a snack, but his focus is always on No. 7.

Van Ginkel calls Astro his best friend, and he also says the pooch is a “chick magnet.”

“Yeah,” Van Ginkel laughs. “I’ve gotten some numbers because of Astro.”

But most of all, Astro is a trusted member of the Van Ginkel family.

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“I think it’s a miracle what he can do for me.  He’s like my son or brother to me,” Van Ginkel says. “I don’t know what I’d do without him.”