MediumO>hreatened miscarriage and Rh prophylaxisca-mccqe1ca-ccfp
A 27-year-old woman at 10 weeks' gestation presents to a remote nursing station with painless vaginal bleeding and no products passed. She is Rh negative, haemodynamically stable. Ultrasound is not immediately available. Which is the most important immediate management step in addition to arranging transfer?