“High-dose hook effect” - negative urine β-HCG in molar pregnancy

Molar pregnancy with false negative urine hCG: the hook effect.

Urine pregnancy tests are widely used in emergency departments as the first screening test for patients of reproductive age presenting with gynaecological problems in order to rule out pregnancy. Conditions such as complete molar pregnancy, which produces large amounts of beta human chorionic gonadotropin (beta-hCG), may cause a false negative result due to an oversaturation of the assay system...

Molar Pregnancy with False Negative β-hCG Urine in the Emergency Department

This case describes an atypical presentation of molar pregnancy in an emergency department patient with abdominal pain and vaginal bleeding. The patient demonstrated clinical features of hydatidiform mole, including acute discharge of a large, grape-like vesicular mass, despite multiple negative urine pregnancy tests. These false-negative qualitative human chorionic gonadotropin assays were lik...

The “hook effect” causing a negative pregnancy test in a patient with an advanced molar pregnancy

•At high hCG levels in molar pregnancies, a "hook effect" can cause an artificially negative value.•Delay in diagnosis of a molar pregnancy due to the "hook effect" can lead to severe complications.•Suspicion of a molar pregnancy should be communicated so a diluted sample is used to quantify hCG.

"Tandem ICON hCG" urine pregnancy test evaluated.

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"High-dose hook effect" with the Centocor CA 125 assay.