Rh immune globulin dose (fetomaternal hemorrhage)
Number of 300 µg RhIG vials from a Kleihauer-Betke or flow cytometry result.
Inputs
1 of 2%
mL
When to use
- RhD-negative patients after a sensitizing event with a positive fetal cell screen.
Pearls and pitfalls
- One 300 µg vial covers 30 mL of fetal whole blood (15 mL red cells).
- Give within 72 hours.
Why use
Standard blood-bank arithmetic.
Fetal whole blood (mL) = fetal cell % × maternal blood volume; vials = fetal blood ÷ 30, rounded (down if decimal < 0.5, up if ≥ 0.5), plus 1