4.9 Hemolytic Disease of the Fetus and Newborn Flashcards

1
Q

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

A. High concentrations of Wharton jelly on cord blood cells
B. Immune anti-A from an O mother on the cells of an A baby
C. Immune anti-D from an Rh negative mother on the cells of an Rh-positive baby
D. Immune anti-K from a K-negative mother on the cells of a K-negative baby

A

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

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2
Q

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?

A

Issue one full dose of RhIg

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3
Q

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

A

Perform an antibody identification panel; titer, if necessary

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4
Q

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

A. Intrauterine transfusion
B. Plasmapheresis on the mother
C. Transfusion of antigen-positive cells to the mother
D. Middle cerebral artery peak systolic velocity (MCA-PSV)

A

Transfusion of antigen-positive cells to the mother

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5
Q

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

A

Obtain a heelstick sample

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6
Q

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

A

Monitor the mother’s antibody level

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7
Q

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

A

Yes, if the baby’s type is Rh positive

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8
Q

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

A

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

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9
Q

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?

A

Molecular testing is indicated to ascertain the type of weak D

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10
Q

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

A. B-positive mother; B-negative baby; first pregnancy; no anti-D in mother
B. O-negative mother; A-positive baby; second pregnancy; no anti-D in mother
C. A-negative mother; O-negative baby; fourth pregnancy; anti-D in mother
D. AB-negative mother; B-positive baby; second pregnancy; anti-D in mother

A

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

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11
Q

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

A

4

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12
Q

Kernicterus is caused by the effects of:

A

Unconjugated bilirubin

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13
Q

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?

A

Perform plasmapheresis to remove anti-E from the mother

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14
Q

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

A

ABO, Rh, antibody screen, and crossmatching

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15
Q

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

A. AB negative, CMV negative, Hgb S negative; irradiated or O negative, CMV negative, Hgb S negative
B. AB positive, CMV negative; irradiated or O positive, CMV negative
C. AB negative only
D. O negative only

A

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

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16
Q

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

A. Forward ABO typing
B. Antibody screen
C. Rh typing
D. DAT

A

Antibody screen

17
Q

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

A

They have received RhIg

18
Q

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?

A

Maternal anti-A, B coating the infant RBCs

19
Q

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?

A

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