How long is LH in your body for?

[SugarFairy]

My friend gave me a pile of ovulation strips that are dated October so I figured WTH I may as well use them. Curiosity got the better of me last night and I got a very very faint positive. How long does LH stay in your body for to give you a positive result on a OPK? The back of the test says that a faint reading is negative and only a strong reading is positive. So does this mean I am going to ovulate soon or that I alreaady have?
Opinions appreciated

 

[LOULOU8888]

hi ive used opks for a couple of years now and lh is in your body all the time but at low levels and it is possible that you will have a faint line at all times through out the month, its only around the time of ovulation the surge in lh happens so your line becomes a dark as the test line. If the line is the same colour or darker your about to ovulate, if its nearly as dark means that your a couple of days off and if its faint its when your not ovulating

 

[SugarFairy]

Thank you LOULOU, now I know. I honestly had no idea!