Who called from 3363156100

a machine from this number called me a [***] and hung up

It was a robo call and they said they were my Doctors Lab and they knew my name. If that was the correct name I should press one and if not press 2.
I hung up. My doctors lab does not use robo calling.

Received a call from 336-315-6100. Voice message saying "This is the Lab calling Maggie....please call 877-528-3720....I'm not expecting lab results.

Called my Vonage phone claiming to be my Wife's Doctor's Lab. Said to call 18775283729. Repeated number and then hung up.

Comes from Spectrum Labs in Greensboro, NC.  They're legit.

Medical offices use their Spectrum Lab's diagnostic services and bill you separately from your doc's office.  I had $15 charge I forgot about, and they called me 3 months later after the tests had been performed.