An invalid pregnancy test result indicates that the test did not function correctly and the outcome, whether positive or negative, cannot be reliably determined. This commonly manifests as a missing control line, a smeared result, or any deviation from the manufacturer’s instructions regarding expected visual indicators. For example, if the test is supposed to show two lines for a positive result and only the test line appears, or no lines appear at all, the test is considered invalid.
The significance of an invalid result lies in its inability to provide actionable information about a potential pregnancy. Relying on an invalid result could lead to delayed medical care or inappropriate decisions regarding health. Historically, issues leading to inaccurate results were more prevalent due to less sophisticated manufacturing processes; modern tests are generally more reliable but still susceptible to user error or damage.