When can you take a pregnancy test after a shot of hCG? If you have been prescribed medications containing hCG, such as Pregnyl for example, they take a while to leave your body. For most women, the time needed for hCG to totally clear from their systems is 12 to 14 days. While it is possible to take a home pregnancy test before that time, the chance of getting a false positive result is extremely high if you do decide to take your chances. Bearing that in mind, there is no reason you should not take a pregnancy test at around 12 days. Having said that, the time needed for hCG to leave your body also depends on the amounts that you have taken.
It is estimated that the lose dosage of 2,500 IU only takes seven days to leave the body completely, while 10,000 IU injections would take at least 14 days. The conclusion? Waiting to take a pregnancy test can benefit everyone. Not taking a pregnancy test before a missed period always increases the chances that the result indicated by the test is going to be accurate. If you have taken hCG, this is even more true. While it is difficult to wait and be patient, for women who have used medications containing this hormone, the odds of getting a false positive test are so high that waiting simply makes more sense.