Clearblue Digital Pregnancy Test - Two Tests. So accurate... tells you how many weeks. It's like 2 tests in 1 - it first detects if the pregnancy hormone is present with over 99% accuracy from the day of your expected period, and if you are pregnant, it ALSO indicates how many weeks since conception occurred 1-2, 2-3 or more than 3 weeks (3+).. The Weeks Indicator is 93% accurate in detecting when you conceived.. So sensitive you can test up to 5 days before your missed period.