Different ranges?

I am obsessing.  I know that I'm obsessing.  


Dr. Goo.gle has both been a shining light and a dismal corridor when it comes to researching betas.  What I wonder about is why the huge difference in HCG ranges?  


The lab that did my test has the following for their point of reference.


0 - 1 Week: 5-50 
1 - 2 Weeks: 40-300
2 - 3 Weeks: 100-10003 - 4 Weeks: 500-6000


Now, is this according to the last menstrual period or ovulation?  It does not specify.  If it's post ovulation, then I would fall in the 1-2 week range.  If it's according to my cycle, then my beta is far too low to be considered viable.          


Then I found the BC Biomedical Reference guide for all their tests.  Currently I'm about 4 weeks from my last menstrual period (LMP).  


Here are their ranges. 



Time after LMP Expected Range
3rd week (6-71)
4th week (10-750)
5th week (217-7138)


I don't get it.  Why such a difference?    


I hope to God that I can get a second beta on Saturday.  It sucks being in limbo.