Because if you give a dog heartworm meds and they have heartworm, they can have a bad reaction.Shhhhhhhh!!!! The boss might hear you!
Given where you live, why do you bother paying for a heart worm test? They are pretty common in your area in the summer are they not?
Mosquitos. And the larval stage in the skeeter can't survive even one day with temps below 57°F in a 45 day period.
Probably not an issue up there. I know @Blooie insisted on having her dog tested when they moved to WY even though the vet said it would be negative, no heart worm there. Blooie finally believed her after a couple of years.
Or walk in and tell him. Then you can get out of the heat for a couple of minutes.