No, you can't. They'll test you, but it's purely for advisory purposes.
I took mine a week after returning from a month in South Africa eating lobster drowned in garlic butter rather too regularly. Measured 9 on the choronary scale. Checked at GP's a fortnight later... 6 and decreasing.
Cholesterol blood test - the same finger prick as above. There is no disqualifying level, but the possible health risks of a high cholesterol will be explained by the doctor at the time of your examination.