<qa>  What is the serum pregnancy test?5. Negative serum pregnancy test serum HCG if female and of childbearing potential. Since beta-HCG may be falsely elevated as a result of malignancy, women of child-bearing potential who have an elevated serum beta-HCG level are eligible for enrollment if they have two Transvaginal Ultrasound TVUS scans one week apart and serial beta-HCG levels two weeks apart that are inconsistent with pregnancy and a Gynecology consult to ensure that the beta- HCG level was at a value high enough to see pregnancy with TVUS. Subjects must agree to practice effective birth control during the study period. 