When is a home pregnancy compeletly accurate.?

When used as directe: Home pregnancy tests are only accurate when used as directed. This typically means waiting until you've missed your first period or 4 weeks after your last one. Obviously, you then have to follow the directions for use & interpretation. Yes, they can be falsely negative but it's unlikely the further out you are from your lmp. It's even less likely for them to be falsely positive.