Title: 099 RhIG Question Set

TMQOD 12-13-2021 Question 1

Q: A postpartum blood sample from a D-negative woman (estimated blood volume of 5000ml) who delivered a D-positive baby today is received in the laboratory for a rosette test, which is positive. The Kleihauer-Betke test identifies 16 fetal red blood cells out of 2000 RBCs counted.

What is the estimated fetal-maternal hemorrhage (FMH)?
- 0.8 mL (Try again. That answer is not correct.)
- 16 mL (Try again. That answer is not correct.)
- 25 mL (Try again. That answer is not correct.)
- 40 mL (correct) (Congrats!!! You got the Question Correct. The estimated fetal maternal hemorrhage (FMH) is determined by: 16 /2000 x 100% = 0.8% 0.8% x 5000 ml (EBV) / 100% = 40ml bleed or 16/2000 = 0.008 0.008 x 5000ml = 40 ml Reference: Cohn, C.S., ed. Technical Manual, 20th ed Bethesda, MD: AABB, 2020. Chapter 23 & Method 5-2.)
- 54 mL (Try again. That answer is not correct.)

TMQOD 12-13-2021 Question 2

Q: A postpartum blood sample from a D-negative female who delivered a D-positive baby today has an estimated fetal-maternal hemorrhage (FMH) of 40 ml by the Kleihauer-Betke test.

How many vials of 300μg Rh immune globulin (RhIG) should be given? (Note: due to the subjective nature of the Kleihauer-Betke test, add a vial.)
- 1 vial (Try again. That answer is not correct.)
- 2 vials (correct) (Congrats!!! You got the Question Correct. The 300μg dose of RhIG should prevent alloimmunization to the D antigen for up to 30 ml of fetal whole blood. The RhIG dose is determined by: 40 ml FMH / 30ml = 1.333 vials Round down for less than 0.5 (Round up for greater than 0.5): 1.333 = 1 vial Add additional vial: 1 vial + 1 vial = 2 vials of RhIG Reference: Cohn, C.S., ed. Technical Manual, 20th ed Bethesda, MD: AABB, 2020. Chapter 23 & Method 5-2.)
- 3 vials (Try again. That answer is not correct.)
- 4 vials (Try again. That answer is not correct.)