Hemolytic Disease of the Fetus and Newborn
Case Studies
1. A 2 day old infant with HDFN requires an exchange transfusion. What is the
BEST red blood cell product to give this neonate?
2. Case Study:
History:
A newborn male was transferred to your hospital’s neonatal intensive care unit from a
smaller hospital. The mother remained in that hospital and her specimen was not
readily available. The infant’s bilirubin at 12 hours was 9 mg/dL and the Hct. 39%.
The doctor ordered testing in anticipation of transfusion. The results were as follows:
Anti-A Anti-B Anti-D
0
0
3+
Anti-A,B
0
O cells: I II III
0 3+ 0
DAT Poly DAT IgG
4+
4+
Choose the next appropriate steps you would pursue: (More than one answer may be
correct)
A. Test a Lui eluate prepared from the infant’s RBCs, against A1, B and O cells.
B. Prepare an acid eluate from the infant’s RBCs and test that eluate with a panel of
reagent red blood cells.
C. Tell the doctor you must have a sample of the mother’s blood before you can
proceed with testing.
D. Call the hospital where the mother is located to attempt to find her pre-natal
serological and transfusion history.
E. Request that the infant’s father come in for testing.
CLS 422 Clinical Immunohematology I
HDFN –part 2 cases
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It was discovered that the infant’s mother received 2 units of packed red blood cells in
2008 and this was her fifth pregnancy. Her blood type was reported as O Rh positive and
anti-K was present at a titer of 32. Anti-Leb also was detected. It was determined that
anti-K was coating the infant’s RBCs. The neonatologist would like you to prepare a 15
mL syringe of packed RBCs for transfusion to the infant. Please choose the most
appropriate blood from the following:
A. O Rh Negative packed red blood cells (PRBCs), less than 3 days old,
crossmatched with the infant’s serum.
B. A fresh O Rh Positive PRBC unit, washed and irradiated, K neg, crossmatched
with the father’s serum.
C. O Rh Negative PRBCs, 7-10 days old, CMV neg, K neg, crossmatched with an
eluate from the infant’s RBCs and with the infant’s serum.
D. O Rh Negative PRBCs, less than 10 days old, CMV neg, K neg, Leb neg,
crossmatched with the cord serum.
If the infant’s bilirubin continued to rise and the neonatologist decided an exchange
transfusion was in order, what other criteria would you use in preparing a unit of red
blood cells for the exchange transfusion? (More than one answer may be correct)
A. Irradiate the unit
B. Wash the unit
C. Test the unit for Hgb. S
D. Adjust the hematocrit of the unit using Group AB plasma
CLS 422 Clinical Immunohematology I
HDFN –part 2 cases
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3. Case Study:
History:
A 23 year-old woman presented to her obstetrician with a 6-week history of
amenorrhea and said that she and her husband had stopped using birth control.
She had never before been pregnant. At age 9 she underwent appendectomy and
did not know whether she had been transfused at that time. Her uterus was
enlarged, and pregnancy was confirmed by a latex agglutination test for beta
human chorionic gonadotropin performed on her urine. Routine
immunohematologic testing revealed that she was A Rh Negative with a negative
antibody screen.
A. What information relevant to hemolytic disease of the fetus and newborn
(HDFN) is conveyed by the fact that the patient’s blood type is Group A?
B. What information relevant to HDFN is conveyed by the patient’s Rh type?
C. What information relevant to HDFN does the negative antibody screen
convey?
Additional Information:
The patient’s pregnancy proceeded uneventfully through the first and second
trimesters. At 28 weeks a blood sample was drawn and sent to the blood bank
with a request to issue RhIG.
D. What is the rationale for administering antenatal RhIG at 28-30 weeks?
E. What tests should be performed to determine if the patient is a candidate for
antenatal RhIG?
F. What would be the consequences of misidentification of an Rh Positive
woman as Rh Negative?
G. Must these tests be completed before the injection of the antenatal RhIG?
Please explain your answer.
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HDFN –part 2 cases
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H. Would determination of the father’s blood type be useful? Please explain you
answer.
Additional Information:
At 38 weeks’ gestation, the patient went into labor. A Type & Screen confirmed
she was A Rh Negative, Weak D Negative, but her antibody screen was weakly
positive at the AHG phase with screen cells I and II, and negative with screen cell
III. In addition, the DAT result on the infant’s cord blood was positive.
I. What is the probable identity of the maternal antibody?
J. Does this have any impact on her subsequent treatment? Please explain your
answer.
K. Why is the cord blood DAT positive?
L. Should an eluate be prepared from the cord RBCs?
M. What further testing is required to determine if the woman is a candidate for
postpartum RhIG?
Additional Information:
A Kleihauer-Betke test revealed 1% fetal RBCs in the maternal circulation.
N. Describe the principle of the Fetal-Maternal Hemorrhage (FMH) screen and
Kleihauer-Betke tests.
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HDFN –part 2 cases
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O. What is the standard postpartum dose of RhIG in the United States? For how
large an antigenic stimulus of fetomaternal hemorrhage can this dose provide
immunoprophylaxis?
P. Calculate the dose of RhIG that should be given to this patient
Q. Within what time period must the RhIG be administered?
R. What is the half-life of RhIG?
4. When and why would you test an eluate with A and B cells in addition to O cells?
5. Case Study:
History:
A baby boy was born to a 30 year old Gravida V, Para IV woman without
prenatal work-up. The infant was found to be severely anemic (5.8 g/dL Hgb.)
and jaundiced (11 mg/dL bilirubin). A unit of O Rh Negative PRBCs was used
without crossmatching for emergency exchange transfusion. The baby died 12
hours after the transfusion with a 4.5 g/dL Hgb. and 13 mg/dL bilirubin.
Investigation:
- Subsequent antibody screening revealed an anti-c in the mother’s serum
- The c antigen was present on both the infant’s cells and on the cells of the
transfused unit.
Interpretation:
A. What prenatal test could have alerted the doctor to this situation?
B. What testing should have been performed on the donor and the infant’s blood
before transfusion?
CLS 422 Clinical Immunohematology I
HDFN –part 2 cases
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C. Would the use of RhIG after the last pregnancy have prevented this? Please
explain your answer.
6. Case Study:
History:
A 35 year old woman with an uncomplicated prenatal history was admitted to the
hospital in labor. An admission type and antibody screening revealed the woman
as A Rh Negative, Weak D Negative, with a negative antibody screen. Upon
delivery, blood from the umbilical cord was submitted for Rh typing. Testing
demonstrated that the baby was Weak D Positive. An order was generated for Rh
Immune Globulin.
Interpretation:
A. When an Rh Negative woman delivers a Weak D Positive infant, is she a
candidate for receiving Rh Immune Globulin?
B. Since the mother’s admission blood specimen is available, does a post-delivery
sample need to be collected? Why or why not?
C. What is the appropriate way to determine the extent of the fetal-maternal
hemorrhage in this case?
7. A technologist is performing a cord blood evaluation, and gets the following
results:
Reagent:
anti-A anti-B anti-D anti-A,B Anti-IgG Albumin control
Patient results:
4+
1+
3+
4+
1+
1+
The most likely cause for these results is:
A.
B.
C.
D.
Failure to adequately wash off Wharton’s jelly
Centrifuge running too slowly
Infant has bacterial infection
Reagents have been contaminated
CLS 422 Clinical Immunohematology I
HDFN –part 2 cases
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