CHAPTER 4.9

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

High concentrations of Wharton jelly on cord blood cells

Immune anti-A from an O mother on the cells of an A baby

Immune anti-D from an Rh negative mother on the cells of an Rh-positive baby

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

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?

Perform a Kleihauer-Betke test

Issue one full dose of RhIg

Perform a DAT on the infant

Perform an antibody screen on the mother

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

Perform an antibody identification panel; titer, if necessary

No need to do anything until 30 weeks’ gestation

Administer RhIg

Adsorb the antibody onto antigen-positive cells

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

Intrauterine transfusion

Plasmapheresis on the mother

Transfusion of antigen-positive cells to the mother

Middle cerebral artery peak systolic velocity (MCA-PSV)

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

Obtain a heelstick sample

Record the DAT result as positive

Obtain another cord blood sample

Perform elution on the cord blood cells

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

Give Kell immune globulin

Monitor the mother’s antibody level

Prevent formation of K-positive cells in the fetus

Not a problem; anti-K is not known to cause HDFN

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

No, the mother is not a candidate for RhIg because of the positive DAT result

Yes, if the baby’s type is Rh negative

Yes, if the baby’s type is Rh positive

No, the baby’s problem is unrelated to Rh blood group antibodies

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

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

No, the type of the baby is unknown

Yes, but only a minidose regardless of trimester

No, RhIg is given to women at full-term pregnancies only

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?

Molecular testing is indicated to ascertain the type of weak D

Yes, she is Rh positive

No, there is no evidence of a fetal bleed

Yes, based on the automated typing results

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

B-positive mother; B-negative baby; first pregnancy; no anti-D in mother

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

A-negative mother; O-negative baby; fourth pregnancy; anti-D in mother

AB-negative mother; B-positive baby; second pregnancy; anti-D in mother

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?

Induce labor for early delivery

Perform plasmapheresis to remove anti-E from the mother

Administer RhIg to the mother

Perform an intrauterine transfusion using E-negative cells

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

Crossmatching and antibody screen

ABO, Rh, antibody screen, and crossmatching

ABO, Rh, antibody screen

ABO and Rh only

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

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

AB positive, CMV negative; irradiated or O positive, CMV negative

AB negative only

O negative only

Why do Rh-negative women tend to have a positive antibody screen compared with Rhpositive women of childbear

They have formed active anti-D

They have received RhIg

They have formed anti-K

They have a higher rate of transfusion

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?

Anti-D from the mother coating the infant RBCs

An alloantibody, such as anti-K, coating the infant RBCs

Maternal anti-B coating the infant RBCs

Maternal anti-A, B coating the infant RBCs

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?

Let the nurse take the syringe of RhIg, so that she may withdraw 50 μg

Call a supervisor or pathologist

Instruct the nurse that the blood bank does not stock minidoses of RhIg and manipulating the full dose will compromise the purity of the product

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

CHAPTER 4.9

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