Is bhcg measured from first day from last menstrual period? or day of conception ? if i am 5-6 weeks from lmp what expected level?

NOT reliable: The B-HCG test is not reliable for determining age of the developing baby. The B-HCG Quantatative test is more for monitoring issues and assuring it is rising (or in the unfortunate case of a miscarriage, falling, etc.) The "Qualatative test will be either Positive or Negative, but as states the Quantataitve gives broad age ranges not used for or helpful in determining the age. US is best.