Portable machine check for high cholesterol at home?

Avoid wrist machines. Most home BP monitoring machines are good and usually fairly inexpensive, <$50. The ones that work on the upper arm are a bit more accurate than the wrist machines. Also, check your BP in both arms, there may be a significant difference. If more than 10 mmhg, you should get that checked out by a cardiologist. If not, use the arm with the higher of the two measurements. Check it at random times.
Home Testing. I can think of no reason to have a home testing machine for cholesterol problems. (not sure why the other doctor talked about blood pressure). Cholesterol varies from day to day and even probably from meal to meal. Whether one is on medication or not these variations are not important and would lead to no daily change in treatment plan or risk.