G.G.
I acutally used a saliva tester. I bought mine at Walgreens a few years ago and I know they don't carry them anymore because I tried to find one for my sister-in-law. I ended up finding one on e-bay. It's much cheaper...$20 or less and reusable. It seemed to work well for me. I was pregnant with my daughter within two months and one month with my son. Good luck.
If you want more info send me a message!