For a study, researchers sought to assess a quick bedside test for detecting the presence of embryonic or fetal tissue in vaginal blood by detecting alpha-fetoprotein (AFP) and insulin-like growth factor-binding protein 1 (IGFBP-1).
The research involved a prospective cohort. Three groups of women of reproductive age were recruited: the study group, which included pregnant women with first-trimester bleeding, was composed of pregnant women with first-trimester bleeding, while the positive control group included women with confirmed intrauterine pregnancies who underwent dilation and curettage (D&C). Vaginal blood was examined for the presence of embryonic or fetal tissue using lateral flow immunoassay strips that recognize both AFP and IGFBP-1.
Ninety people, including 12 with ectopic pregnancies, 16 with active miscarriages, four with threatening miscarriages, and four with complete losses, were recruited: 31 in the positive control group, 23 in the negative control group, and 36 in the research group. The presence of embryonic or fetal tissue in the vaginal blood of 14 of the 16 people who were experiencing active miscarriages was properly positive. No embryonic or fetal tissue was found in the vaginal blood of any people who had ectopic pregnancies, impending miscarriages, or full losses. The test strips properly detected the presence of embryonic or fetal tissue in the vaginal blood of 45 out of 47 patients, yielding a test sensitivity of 95.7% (95% CI 85.5-99.5%) in all cases. Around 42 of the 43 people with the absence of embryonic or fetal tissue in their vaginal blood confirmed were correctly negative, giving the test a specificity of 97.7% (95% CI 87.7-99.9%) for the population.
Embryonic or fetal tissue can be precisely detected in vaginal blood using a rapid test strip that detects both AFP and IGFBP-1. If this is positive, it may help in making a miscarriage diagnosis and excluding ectopic pregnancy at the bedside.