A 28 years old female at term presents with gush of fluid and regular contractions. Prenatal investigations reveals Rh negative, antibody negative, husband- Rh positive homozygous. After 10 hours her labor progresses and delivered 3600g baby via normal vaginal delivery. Placenta did not separate spontaneously and manual removal was done. The next step of investigation is
RhoGAM Indirect Coomb's test Direct Coomb's test Detection of fetal cells in maternal circulation