Butterfly, in one final attempt to show you the truth, I will quote from Erowid myself.
"Blood Testing
Cannabis is detectable in the blood for approximately 2-3 days after use in an infrequent user. Frequent use can be detected in the blood for approximately 2 weeks." http://www.erowid.org/plants/cannabi..._testing.shtml

Please note that the 2 week time frame is as extreem and rare as the 12 week time frame use in the urine testing section of the same page.

Hope that helps you. N2