The Clearblue ovulation test accurately indicates the 2 most fertile days of each woman™s cycle. Detects an increase in hormone (LH) in the urine, which is secreted before ovulation. It offers more than 99% accuracy and easy reading of results. The appearance on the screen of the smiling face shows a positive result, ie that the fertile day has been detected. The appearance on the screen of the œempty� cycle shows a negative result, ie that no increase in the hormone has been detected.