Following delivery
A D-negative mother who is not alloimmunized to D should also receive an appropriate dose of RhIG after delivery of a D-positive infant. After delivery, a cord blood sample from infants born to D-negative mothers should be tested for the D antigen. If the neonate is D-negative, no further RhIG is needed. However, if the infant is D-positive, the mother should have a postpartum blood sample screened for fetomaternal hemorrhage in order to determine the appropriate dosage of RhIG to be administered. (The presence of residual anti-D from antepartum RhIG administration does not indicate ongoing protection from alloimmunization- repeat administration of RhIG is necessary. )The rosette test is a sensitive method to detect fetomaternal hemorrhage of 10 cc or more. This qualitative (not quantitative) test will be positive if fetal D-positive cells are present in the maternal sample, indicating a significantly large fetomaternal hemorrhage has occurred. A rosette test may be falsely positive if the mother is positive for the weak D phenotype and falsely negative if the neonate is weak D.  If the mother is positive for the weak D phenotype, the rosette test should not be used; instead, a quantitative test such as the Kleihauer–Betke test or flow cytometry should be utilized. If the rosette test is negative, then a dose of 300 micrograms of RhIG is given (sufficient to prevent alloimmunization after delivery in 99% of cases). The RhIG dose suppresses the immune response to up to 30 cc of whole fetal blood (15 cc of red blood cells).
46 may refer to: 

46 (number)
46 (album), a 1983 album by Kino
"Forty Six", a song by Karma to Burn from the album Appalachian Incantation, 2010
One of the years 46 BC, AD 46, 1946, 2046