Hi JohnDoe, The fact that you tested outside of the window period, waited the full 15 minutes before reading your result, was not on any medication that could affect the result of the test and received a control line, suggests to me that you did everything correct and your result is accurate, reliable and conclusive. False negative results are uncommon but obviously do happen every once in a while, but we take every step to mitigate the risk of someone receiving one. It was assessed that the window period is a major factor for someone receiving a false negative result as the test's ability to be able to accurately detect infection is minimised if no antibodies have been produced at time of testing (within the 12 weeks). Your negative result using our test at 16 weeks is accurate and can be relied upon greatly, and your full blood count confirms this. I hope this helps, if you have any other queries, please feel free to leave them below. Thank you, Becky.