Sometimes an hCG test will give a positive result, while a pregnancy test will give a negative result. It should be borne in mind that a blood test for human chorionic gonadotropin is highly sensitive and detects pregnancy in the earliest stages, so you should trust this method.
If the pregnancy test is positive, but the blood test result is negative, then the problem is most likely with the quality of the test strips. That is why, to determine hCG at home, it is recommended to purchase several tests at once - both expensive and cheap.