In order for the strip to show a reliable answer, the concentration of hCG in the urine must reach the appropriate level.
Even modern and super-sensitive devices will not work if the hormone concentration is below 10 mIU/mol.
Thus, it is better to wait and carry out the procedure 1-2 days before the expected date of menstruation. The procedure before the delay is not only not advisable, but also leads the woman astray.