BB 4.9

Question 1

All of the following are reasons for a positive DAT on cord blood cells of a newborn except:

Answer 1

Immune anti-K from a K-negative mother on the cells of a K-negative baby

Question 2

A fetal screen yielded negative results on a mother who is O negative and infant who is O positive. What course of action should be taken?

Answer 2

Issue one full dose of RhIg

Question 3

What should be done when a woman who is 24 weeks pregnant has a positive antibody screen?

Answer 3

Perform an antibody identification panel; titer, if necessary

Question 4

All of the following are interventions for fetal distress caused by maternal antibodies attacking fetal cells except:

Answer 4

Transfusion of antigen-positive cells to the mother

Question 5

Cord blood cells are washed six times with saline, and the DAT result and negative control are still positive. What should be done next?

Answer 5

Obtain a heelstick sample

Question 6

What can be done if HDFN is caused by maternal anti-K?

Answer 6

Monitor the mother’s antibody level

Question 7

Should an O-negative mother receive RhIg if a positive DAT on the newborn is caused by immune anti-A?

Answer 7

Yes, if the baby’s type is Rh positive

Question 8

Should an A-negative woman who has just had a miscarriage receive RhIg?

Answer 8

Yes, but only if she does not have evidence of active anti-D

Question 9

SITUATION:. The automated blood bank analyzer reports a type of O negative on a woman who is 6 weeks pregnant with vaginal bleeding. The woman tells the emergency department physician she is O positive and presents a blood donor card. The MLS performs a test for weak D and observes a 1+ reaction in the AHG phase. The Kleihauer-Betke test result is negative. Is this woman a candidate for RhIg?

Answer 9

Molecular testing is indicated to ascertain the type of weak D

Question 10

Which of the following patients would be a candidate for RhIg?

Answer 10

O-negative mother; A-positive baby; second pregnancy; no anti-D in mother

Question 11

The Kleihauer-Betke acid elution test identifies 40 fetal cells in 2,000 maternal RBCs. How many full doses of RhIg are indicated?

Answer 11

D. 4

Question 12

Kernicterus is caused by the effects of:

Answer 12

Unconjugated bilirubin

Question 13

Anti-E is detected in the serum of a woman in the first trimester of pregnancy. The first titer for anti-E is 32. Two weeks later, the antibody titer is 64 and then 128 after another 2 weeks. Clinically, there are beginning signs of fetal distress. What may be done?

Answer 13

Perform plasmapheresis to remove anti-E from the mother

Question 14

What testing is done for exchange transfusion when the mother’s serum contains an alloantibody?

Answer 14

ABO, Rh, antibody screen, and crossmatching

Question 15

Which blood type may be transfused to an AB-positive baby who has HDFN caused by anti-D?

Answer 15

AB negative, CMV negative, Hgb S negative; irradiated or O negative, CMV negative, Hgb S negative

Question 16

All of the following are routinely performed on a cord blood sample except:

Answer 16

Antibody screen

Question 17

Why do Rh-negative women tend to have a positive antibody screen compared with Rh- positive women of childbearing age?

Answer 17

They have received RhIg

Question 18

SITUATION: An O-negative mother gave birth to a B-positive infant. The mother had no history of antibodies or transfusion. This was her first child. The baby was mildly jaundiced, and the DAT result was weakly positive with polyspecific antisera. What could have caused the positive DAT result?

Answer 18

Maternal anti-A, B coating the infant RBCs

Question 19

SITUATION: RhIg is requested on a 28-year-old woman with suspected abortion. When the nurse arrives in the blood bank to pick up the RhIg, she asks the MLS if it is a minidose. The MLS replies that it is a full dose, not a minidose. The nurse then requests to take 50 μg from the 300 μg syringe to satisfy the physician’s orders. What course of action should the MLS take?

Answer 19

Instruct the nurse that the blood bank does not stock minidoses of RhIg, and relay this information to the patient’s physician