Is one line on a pregnancy test mean pregnancy?

Patient's question:

Last menstrual period was around the 7th
Had sexual intercourse but did not ejaculate
Used a pregnancy test strip to test morning urine
It showed one dark line and one faint line
What could be the situation?
Thank you

Doctor's answer:

The self-testing accuracy of early pregnancy test strips is 75%. Results are effective within 5 minutes. False negative or false positive results may occur. It is more accurate to test 10 days after a missed period. A menstrual cycle delay of about one week is generally still within the normal range. In your case, if you are concerned about pregnancy, you can closely monitor your situation. If your period is delayed by more than one week, it is recommended to visit a regular hospital's gynecology department for blood HCG, ultrasound, and other relevant tests to confirm pregnancy.