There are home pregnancy tests for dogs, such as the Witness Relaxin test, that can be purchased online and used by owners to determine if their pet is pregnant. These tests detect the presence of the hormone relaxin, which is produced by the placenta after implantation and can be detected in the blood or urine of pregnant dogs. However, it is important to note that the accuracy of these tests may vary, and false negative or false positive results can occur. Additionally, while the test can be performed as early as 20-21 days after the luteinizing hormonal surge, it is generally recommended to wait until at least 28 days after breeding before performing the test to ensure the most accurate results.