It is possible for a pregnancy test to accurately detect pregnancy before a missed period, although the accuracy may vary depending on the sensitivity of the test and individual factors. Light spotting could be implantation bleeding, which occurs when the fertilized egg attaches to the uterine lining. This can happen around the time of your expected period. If you received a positive result on your pregnancy test, it is likely that you are pregnant. However, it is always recommended to confirm with another test or consult with a healthcare professional for further guidance. Retesting after a few days or consulting with your doctor will provide more clarity and ensure accuracy in confirming your pregnancy status.