It was concluded that presence ofcannabinoids in urine or blood is not unequivocal proof of active cannabissmoking. Giardino 25 26 found THC-acid levels of up to 30-50ng/ml from passive-exposed subjects, and recommended a threshold of 65ng/ml to differentiatebetween active and passive smoking of cannabis.ticht & Kaferstein 20 estimated that the blood THC concentrationsproduced in a 70kg person smoking 15mg THC would peak at 7-8 minutes,after 30 minutes between 14-42ng/ml, and at 60 minutes between 7.5-14ng/ml.3.3 McBay 21 compared THC and THC-COOH levels in a study involving smokedmarijuana cigarettes.
Calculation Using An ovulation Calendar: 1  The first day of a period is considered as day 1. 2  Usually on day 14, the egg is released and is waiting for the sperm to fertilize it. 3  The egg has a lifespan of just 12 to 24 hours whereas a sperm can last for about 72 hours in a woman.
IVF Due Date Calculator. As far as calculating a due date after IVF, the most accurate method is to add 266 days (or 38 weeks) to the day of the egg retrieval. The eggs are fertilized that day, which is the same as day 14 - the day of ovulation and fertilization in a normal 28 day menstrual cycle.VF Due Date Calculator. As far as calculating a due date after IVF, the most accurate method is to add 266 days (or 38 weeks) to the day of the egg retrieval. The eggs are fertilized that day, which is the same as day 14 - the day of ovulation and fertilization in a normal 28 day menstrual cycle.