Because I wasnt sure the Home Health brand was working for me. Home Health is the green, and Clinical Guard is the blue. I previously thought I might have ovulated sometime Thursday night (the 29th). Hubbs and I did BD that night just in case. Then I was getting extremely negative results every day following the 29th. Now I changed test brands and I'm still getting a negative, but its darker than most of the others I took of the Home Health brand. Does anyone use Clinical Guard? Do you think it is accurate? Also, do you think I may have ovulated on the 29th?