Q: How accurate are urine home pregnancy tests (HPTs) on the first day of a missed period?
A: According to an October 2001 article in JAMA about 80% of pregnant women will have a positive HPT on the first say of there missed period. The remaining 10% of women may have a negative test because there was delayed implantation of the fertilized egg. The highest possible screening sensitivity of a home pregnancy test done one week after the first day of the missed period is 97%