Generally 7~10 days after ovulation, you can test for pregnancy.
Sperm and egg combine to form a fertilized egg, and the trophoblast cells will secrete human chorionic gonadotropin (HCG) when the fertilized egg is deposited. Generally, HCG will start to be produced 7~10 days after ovulation, and since the value of HCG at this time is relatively low, the blood test is more sensitive, and pregnancy can be detected in general, while the test result of pregnancy test paper may show a false-negative result.
Whether it is blood test or pregnancy test, if the result is negative after ovulation, it may be related to the HCG value is too low or delayed ovulation, etc. You can take blood test or urine HCG test again after 1 week to confirm whether you are pregnant.