how long does a positive opk last??

Renae • 💙 '09....💙 '11....💔 '14.... 💔 '14....💔 '15....💔 '16....💔 '17....💜 12/12/17
opk last??" />
I ordered some opk'S online and they arrived midway though my cycle. so I took my 1st test the day I got them and it was a slight positive. I continued to take the opks for about 7days after in which they became clear negatives. but im curious to know..if I got a slight positive on cd18 then negatives...how many days b4 would it have been a TRUE positive??

Vote below to see results!