A 14-Year-Old Female With Abdominal Pain and Vaginal Bleeding

Determining pregnancy status is vital in the approach to adolescent females with abdominal pain or vaginal bleeding. The prognosis of extrauterine pregnancies and gestational trophoblastic disease depends greatly on the ability to make an early diagnosis. Urine qualitative β human chorionic gonadotropin (β-hCG) tests are routinely used in emergency departments for pregnancy screening. However, point-of-care testing can be misleading in molar or late first-term pregnancies when β-hCG levels are extremely high. We report a case of an adolescent female presenting with a molar pregnancy in which point-of-care pregnancy testing was falsely negative due to the “high-dose hook effect.” The “hook effect” affects almost all current qualitative assays and highlights the dangers of reliance on a single laboratory test.