When can I do the Test? When you start testing depends on your usual cycle length. Below is a simple chart that will tell you when in your cycle you should start testing. https://www.clearblue.info/uk/gims/content/image/image195161.jpg It is important that you haven't urinated for at least 4 hours before doing the test, because this ensures that the hormone level in your urine is concentrated enough for the test to detect. You can test at any time if the day, but it should be at the same time each day. Also don't use first morning water - I did Most girls suggest between 12-3 in the afternoon.