一位20歲女性病息，因為月經週期延遲而來求診，懷孕試驗為陽性反應，人類絨毛膜性腺激素(β-hCG)使用IRMA方法測定為486.05 mIU/mL .病患隨後接受手術，病理檢查證實為水囊狀胎塊。後來將原檢體經過連續稀釋後重新檢驗，發見β-hCG實際是大約627，000mIU/mL，證實是由於hook effect所致。Hook effect雖然 很少見，但是可能影響臨床的診斷和治療，本文將探討有效的偵測方法。

A 20-year-old female visited our hospital due to delayed menstruation. Pregnancy test showed positive result. Serum level of-hCG (human chorionic gonadotropin， B-subunit) was 486.05 mlU/mL using an IRMA method. The patient received an operation of suction D&C under the impression of molar pregnancy. Hydatidiform mole was proven by pathologic examination. A retest of the original blood sample after serial dilution was performed and the exact B-hCG value of this patient before operation was 627，000 mlU/mL. We considered the incorrect B-hCG result in previous test might be secondary to hook effect in IRMA method. Hook effect occurs infrequently but may have serious clinical implications. In this artic， the authors would like to discuss the effective detection methods