5 weeks since my last period can a pregnancy test be accurate if taken?

Yes: At "5 weeks since your last normal period", most urine pregnancy tests performed on a morning first-urine voiding will be reasonably accurate. False positive and false negative results are possible depending on the test..A blood betaHCG pregnancy test will usually be accurate if performed 10 to 12 days after fertilization and is more reliable .False positive or false negative results are rarer.