Negative beta hCG: positive ectopic pregnancy

Case report A previously healthy 21-year-old woman presented to the Emergency Department (ED), Auckland Hospital, with a four-hour history of sudden onset, severe, constant, generalised abdominal pain radiating to back and shoulder tip. Initial rise to certain maximal levels in EP may be followed by declining levels of hCG.2 Negative urine and serum hCG tests are reported among 3.1% and 2.6% of EP cases respectively.3 Serum tests are considered more reliable than urine,4 with false-negative results among up to 17.5% of urine and 2% of serum tests involving positive EP.4 Auckland Hospital Laboratory utilises ProClinic One-Step Urine HCG Pregnancy Test for urine and Elecsys 1010/2010 HCG STAT Immunoassay Test for serum.