False negative pregnancy tests

False negative pregnancy tests can result in undesirable outcomes (including loss of pregnancy) if inappropriate treatment is given. In a recent study evaluating the performance of devices used in a hospital setting, 9 of 11 devices were found to be susceptible to false negative results when used to test urine solutions containing hCGβcf concentrations observed in normal pregnancy.

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False negative pregnancy tests: the story continues 

Source: The Pregnancy Lab