Youre exactly right - you should, or rather need to test yourself and see. Nobody can realistically answer your question because each person is different and there are too many variables to take into account to even arrive at a guesstimation.

If this test is for a job, and I'm thinking that getting the job means alot to you, would you rather rely on a home test result rather than guesswork from others?

When testing yourself, be sure to use the first urination of the day.