This case stresses the importance of laboratory results in the interpretation of ultrasonographic findings of free pelvic fluid when querying an ectopic pregnancy.  At the time of scanning, the serum beta HCG value was unavailable but the urinary beta HCG was known to be positive with the LNMP 2 months prior to the study.  

The findings of complex free fluid and an absent intrauterine gestation sac requires interpretation in conjunction with the beta HCG level.  If the beta HCG is greater than 2000 IU, the findings are indicative of a ruptured ectopic pregnancy, in this case likely within the left adnexa.  

The serum beta HCG in this case was found to be 2243.

Acknowledgment: Dr Shalini Amukotuwa and Dr Janette M Vincent