WHAT DOES THIS MEAN ??

Patient: Hi my boyfriend and i had, had sex. i went to the doctor’s 4 days later and done a pregnancy test. The doctor told me that i was 40% negative .. i asked if that means I’m 60% positive and he said yes.. he also referred me to get a blood test. i asked my boyfriend if he had came in me. he said a tiny amount . what did the doctor mean by 40% negative and 60% positive .. also can u get pregnant off a tiny amount of sperm, or pre-cum?

Doctor: