Can LH surge be detected after ovulation?

Ok, so I am using the ovulation test strips with the lines to try my best to have intercourse at the right time to conceive.  On day 13 of my cycle I tested and the control line matched the test line exactly, day 14, the test line was darker,day 15 the test line even darker, and today, day 16 the test line is still darker than the control line, but shouldn't I have ovulated already?  My question is: how long after ovulation can LH still be detected?

[sydneysummer]

my LH is usually elevated for 3 days or so.  my doctor says that is not unusual.  he also said it doesnt really matter and to stop testing after you get the first positive (of course I keep testing anyway).  i know that if it is elevated for too long it could mean a problem with your cycle.  if it continues to do that for several months I would ask your doctor.