In this Practice article by Sheikha Al-Jabri and colleagues (BMJ 2010;341:c3770, doi:10.1136/bmj.c3770), the authors confirm that they made errors in the references. Reference 8 in the reference list was wrong and should not have been cited. The third paragraph of the “investigations” section (in which reference 8 was cited) should have been referenced as follows (note that the numbering here does not relate to the published numbering):

“In primary care, transvaginal ultrasound may not be readily available and transabdominal ultrasound is considered a useful screening test for early pregnancy complications, with a sensitivity of 80% and specificity of 78%.1 Finding an intrauterine gestation on abdominal scan effectively excludes the possibility of an ectopic pregnancy. However, ultrasound diagnosis should be made by visualising an adnexal mass rather than the absence of intrauterine sac only.2 For more definitive diagnosis, the sensitivity of transvaginal ultrasound to diagnose tubal ectopic pregnancy is 90.9% and the specificity is 99.9%.2”