This was brought up a while back regarding faintness of lines. Some agree that faintness of lines does matter and some disagree. Your lab test is going to be a little more extensive but the home test are quite accurate. Lab testing uses immunoassay first then confirms non-negative results using GC/MS. If your wife is passing the home test I give her a 99% chance of passing the lab test.

Was she diluting to pass or was this a first void of the day pass? Also, was the test line dark or faint?