High HCG Levels

Ka

I went to my PCP yesterday for a sore throat and tested positive for strep and she offered to run labs for me while I was there. I was <a href="https://play.google.com/store/apps/details?id=com.glow.android">tracking ovulation</a> and am pretty 100% on my dates but today her nurse called and asked if I could be off because my HCG is 8534 (pretty high for 4 weeks 5 days) and suggested I contact my OB for a scan. Has this happened to anyone else? What would cause levels to be so elevated?