If u take pregnancy test what could be the reason u get a negative are u test to soon before missed period ?

Reasons: Any time you do a quantitative test you have to set numerical limits as to what you count as positive and what you count as negative. When you got a 64 on a test you were told you failed but your friend who got a 65 passed. Very little difference but one was on one side of the line and one was on the other. The dividing lines position is somewhat arbitrary.