How accurate is a pregnancy blood test on first day of missed period?

Pregnancy testing: The bigger question is is the test done at least fourteen days after the possible conception. If it is less than fourteen days then it is not too accurate.

Very accurate: It is very accurate on first day of missed period.It usually become positive 7 to 12 days from conception in most cases it will be positive when you miss your period.

99.9%: Pretty good.