4 days past ovulation i am in cycle 20. my basal body temp is been 98. 8. my period is due sept 5 how long i have to wait to do pregnancy test?

Pg test: The first morning urine on the day your period would be due is the first accurate time. If the test is negative, it needs to be followed up in a week if no pregnancy.

Wait a few...: generally the earliest you should test is 1-2 days before the expected period. If you have a certain ovulation date you can count about 11 days from that. There may still be false pos/false negs if you test this early, but it's mostly reliable.