Chapter 12

Anti-D in the serum of a third-trimester pregnant woman with a titer of 16 is indicative of:

active immunization (antibody titer of 16 or more suggest active immunization and not the presence of anti-D from Rh immune globulin) page 283

amniotic fluid analysis showed a marked increase into zone 3 of the liley graph. Lecithin-sphingomyelin ratios indicated that the fetal lungs were not mature. Select the most appropriate decision regarding medical intervention.

an intrauterine transfusion (Because fetal lung maturity is essential for early delivery, intrauterine transfusion is necessary to provide red cells to the fetus to replace those cells destroyed by the mother's antibody) page 284

All of the following are goals of an exchange transfusion except to:

correct anemia. Page 292

Which of the following best describes the principle of the Kleihauer-Betke test?

fetal hemoglobulin is resistant to acid elution and remains in the cell to stain pink, whereas adult cells appear as ghost cells. The Kleihauer-Betke acid elution test is a stain that enables the quantification of fetal cells in the maternal circulation page 290

A large fetomaternal bleed in a D-negative woman who delivered a D-positive infant should be suspected if the:

fetomaternal hemorrhage screen result is positive ( The fetal screen determines whether the mother has received a significant amount of D-positive cells from the baby during birth) page 289

A newborn phenotypes as group O, D-positive with a 1+ direct antiglobulin test. The mother's antibody screening test is negative. Assuming the antibody screen is valid, one should consider the reason for the positive DAT is due to an antibody against __________ antigen.

low-incidence (The screening cells might not have the low-incidence antigen to which the antibody is reacting) page 282

Why is reverse grouping omitted in the neonatal period for ABO testing?

newborns do not produce their own antibody until about 4 months page 287

In testing amniotic fluid, the Liley method of predicting the severity of hemolytic disease of the fetus and newborn is based on

optical density of bilirubin at 450 nm. (in the liley method, optical density reading at 450 nm determines the concentration of bilirubin) page 284

A weakly reactive anti-D was detected in a sample from a D-negative mother one day following delivery of a D-negative baby. Based on these results, what is the next step?

review records for prenatal RhIG administration (Weak anti-D is often detected in samples obtained from D-negative mothers who received prenatal RhIG. No additional RhIG is necessary since the baby is D-negative. ) page 286

The Kleihauer Betke test was performed using a 1-hour post-delivery maternal blood sample. Results: 10 fetal cells/1000 cells counted It is the policy to add 1 vial of Rh immune globulin to the calculated dose when the estimated volume of the hemorrhage exceeds 20 mL of whole blood. Calculate the number of vials of Rh immune globulin that would be indicated under these circumstances.

3 10/1000=1% bleed 1 x 50= 50(50mL of fetal blood in the mother's circulation) 50/30= 1.66 ( 30mL bleed is protected by 1 vial of Rh immune globulin) 1.66-> 2 (round up) 2 + 1= 3 doses ( one added for safety margin) page 290

Select the most common antibody specificity associated with hemolytic disease of the fetus and newborn

Anti-A,B (Anti-A,B from group O mother can cause mild hemolytic disease of the fetus and newborn if the baby is group A or B) page 281

A group O, D-positive mother gave birth to a group A, D-negative infant. After 24 hours, the newborn's bilirubin level rose to 19 mg/dL. A direct antiglobulin test performed on the cord blood specimen was positive with anti-IgG. What antibody is most likely implicated?

Anti-A,B ( ABO hemolytic disease of the fetus and newborn is typically seen in group O mothers with infants who are group A) page 286

Which one of the following antibodies is unlikely to cause hemolytic disease of the fetus and newborn?

Anti-Lea (Lewis system antibodies are IgM and therefore do not pass the placenta. The Lewis system antigens are not well developed at birth) page 282

Rh immune globulin cotains

IgG anti-D (Rh immune globulin is a pool of purified human plasma containing IgG anti-D) page 288

Select the situation where the administration of Rh immune globulin would be contraindicated.

Mother- r"r; 4+ anti-D detected Newborn- R2r: DAT positive (Rh immune globulin is not indicated if anti-D has already been formed) page 289

During a first-trimester prenatal examination, a pregnant group A, D-negative woman had an anti-D titer of 8. What is the most likely course of action?

Repeat the titer in 4 weeks to determine if significant rise in titer is detected. (A change in titer suggests the need for more invasive tests.) page 283

The rosette test will detect a fetomaternal hemorrhage as small as

10 mL page 289

A 0.3% fetomaternal bleed was determined by a Kleihauer-Betke stain of postpartum blood. What is the estimated volume of the fetomaternal bleed expressed as whole blood?

15mL (0.003 ´ 5000 (average blood volume of an adult) = 15 mL) page 291

A 300-µg dose of Rh immune globulin contains sufficient anti-D to protect against how much whole blood?

30 mL (Rh immune globulin protects against a bleed of 30 mL of D-positive cells from the fetus or newborn to the mother before or during birth.) page 289)

Following delivery, when should Rh immune globulin be administered?

72 hours (Clinical trials for Rh immune globulin established a 72-hour time for the administration of Rh immune globulin following delivery.) page 289

What type of hemolytic disease of the fetus and newborn affects the first-born?

ABO (Because ABO antibodies are present before red cell exposure, ABO antibodies can cause hemolytic disease of the fetus and newborn on the first pregnancy.) page 281

which test are performed to identify the cause of suspected hemolytic disease of the fetal and newborn

ABO group, D testing, DAT page 286

To be considered a candidate for Rh immune globulin, the mother is ______________ and the infant is _____________.

D-negative, D-positive (Rh immune globulin protects only the formation of anti-D in a D-negative mother who has a D-positive infant.) page 289)

To prevent graft vs host disease RBC's prepared for infants who have received intrauterine transfusions should be:

Irradiated (Because the fetal immune system is immature, providing components that are irradiated to prevent leukocyte replication is necessary) page 287

Which elution method is ideal in the investigation of ABO hemolytic disease of the fetus and newborn?

Lui freeze-thaw The Lui freeze-thaw elution method is a sensitive and fast method to determine whether ABO antibodies are coating the baby's red cells. page 205

Select the true statement regarding ABO hemolytic disease of the fetus and newborn

The frequency of ABO hemolytic disease of the fetus and newborn is greater than Rh hemolytic disease of the fetus and newborn. (ABO system hemolytic disease of the fetus and newborn is more common because the occurrence of group O mothers having group A babies is more frequent) page 281

All of the following are common characteristics of ABO hemolytic disease of the fetus and newborn except

The mother is group A (often the mother was group O and passed an IgG form of anti-A,B to the infant page 281

In a suspected case of ABO HDFN, what significant information is obtained from the baby's blood smear?

The presences of spherocytes (Spherocytes are characteristic of ABO HDFN but not normally observed in Rh HDFN.) page282

Which of the following is true regarding the rosette test?

The test is valid only if the mother is D-negative and the infant is D-positive (The rosette test is a qualitative test to determine D-positive infant's cells in the D-negative maternal circulation) page 289