HCG levels and twins

I am curious of anyone out there had levels similar to this.. I had IVF 5 day single embryo blastocyst transfer on Oct 29.

Nov 7th (9 days post transfer) - HCG 104
Nov 10th (12 days post transfer) - HCG 511
Nov 14th (16 days post transfer) - HCG 4525
Nov 17th (19 days post transfer) - HCG 10300

Could this mean twins?? I have my first U/S on Nov 21!! I was wondering if anyone else had numbers like this!!

[waitingwithhope]

Here is a website with charts...thought this might help. Congrats!
http://www.advancedfertility.com/earlypre.htm

[spade22]

Your HCG levels for 19 days post transfer (~5 weeks gestational age of fetus) are well within the norm for a singleton pregnancy in which HCG levels typically range from ~800-20,000.

Congratulations and good luck with your pregnancy.