9. Perinatal Testing and HDFN

Question 1

3 categories of HDFN and which is most common

Answer 1

Rh(D) - most severe
ABO - milder, MOST COMMON
Other IgG antibodies

Question 2

HDFN was previously called..?

Answer 2

Erythroblastosis fetalis

Question 3

Main problem that affects the fetus in HDFN?

Answer 3

Anemia

Question 4

Main problem that affects the newborn in HDFN?

Answer 4

Anemia + bilirubin accumulation

Question 5

Whose liver conjugates indirect bilirubin?

Answer 5

Maternal liver

Question 6

When edema occurs in the peritoneal and pleural cavities it’s called..?

Answer 6

Hydrops fetalis

Question 7

Previously, about __% of HDFN cases were caused by antibodies in mother directed against the Rh D antigen

Answer 7

95%

Question 8

In what scenario would a second dose of Rhogam be given to the mother?

Answer 8

after delivery (within 72 hrs) IF the baby is Rh pos

Question 9

In what scenario would a 1st dose of Rhogam be given to a mother?

Answer 9

If they’re Rh NEG - 28 weekks pregnancy

Question 10

ABO HDFN is usually caused by mother having group __ blood and baby has ________

Answer 10

Mom - group O

Baby - A/B/AB

Question 11

This blood group is more likely to have higher titred IgG antibodies than any other ABO group

Answer 11

Group O

Question 12

Hyperbilirubinemia and jaundice within 12-48 hrs of birth is treated with _________

Answer 12

phototherapy

Question 13

Other than anti-D, the most common and significant antibodies are anti-__ and anti-__

Answer 13

anti-c

anti-K

Question 14

Most significant non-Rh system antibodies?

Answer 14

Kell

Question 15

3 less common HDFN-causing antibodies?

Answer 15

anti-E
anti-C
anti-Fya

Question 16

Reciprocal of the last tube with macroscopic agglutination

Answer 16

Titre

Question 17

When is a antibody titre significant?

Answer 17

When there’s 2 tube differences (e.g. 1st titre = 8, 2nd tire = 32)

Question 18

Value assigned for agglutination strength

Answer 18

Titre score

Question 19

Before Doppler ultrasonography, __________ was used to measure severity of HDFN

Answer 19

aminocentesis

Question 20

What does Doppler ultrasonography measure?

Answer 20

Speed of RBC circulation in fetus

faster = less viscous = less hgb

Question 21

Graph used to predict severity of HDFN during pregnancy by evaluation of amniotic fluid

Answer 21

Liley graph

Question 22

What is measured in amniocentesis

Answer 22

Bilirubin pigment in amniotic fluid (spectrophotmetric scan)

Question 23

Fetal sample taken from umbilical cord using ultrasound guided needle

Answer 23

Cordocentesis

Question 24

When is screening for fetomaternal hemorrhage necessary?

Answer 24

Mom - D neg

Baby - D pos

Question 25

When is Kleihauer-Betke test necessary?

Answer 25

When fetal screen (rosette) is positive to determine dosage of RhIG

Question 26

What does the rosette test detect?

Answer 26

Any Rh positive cells (not specific for fetal cells!)

Question 27

Appearance of fetal and adult cells in Kleihauer-Betke stain and why they appear that way

Answer 27

Fetal cells = pink Adult cells = "ghost" cells Fetal cells w/ Hgb F resist acid

Question 28

Mother is D-negative and has anti-D in serum. RhIG candidate?

Answer 28

No - review history to ensure anti-D isn't from RhIG administration and is immune anti-D

Question 29

Autoimmune disease caused by platelet autoantibodies

Answer 29

Primary immune thrombocytopenia AKA idiopathic thrombocytopenic purpura (ITP)

Question 30

Intravenous RhIg is approved for the treatment of acute and chronic ITP in what type of patient?

Answer 30

Rh-POS patients who have NOT been splenectomized

Question 31

Another use of RhIg?

Answer 31

Treatment of platelet autoimmune disease

Question 32

Sample for post-partum serological testing of cord blood is taken from the ________ vein

Answer 32

umbilical

Question 33

Why must post-partum cord blood be washed several times before testing?

Answer 33

Avoid false positives due to contamination from Wharton's jelly

Question 34

Type of blood used for intrauterine transfusion?

Answer 34

``` O neg Fresh, washed Irradiated CMV neg Hgb S neg ```

Question 35

This method is used primarily to remove high levels of unconjugated bilirubin after baby delivery

Answer 35

Exchange transfusion *Rarely required due to phototherapy and IVIG now

Question 36

How does IVIG (intravenous immune globulin) work?

Answer 36

It competes w/ mother's antibodies for Fc receptors on macrophages in infant's spleen = reduces amount of hemolysis