HDN

Question 1

list the most common/significant antibodies that cause HDN

Answer 1

anti-E anti-c anti-C anti-K anti-Fy^a

Question 2

what is the prenatal testing required ?

Answer 2

• History of pregnancy & Transfusion
• ABO group
• Rh typing (including weak D)
• antibody screen

Question 3

if the anti-body screen is negative when should we repeat the testing?

Answer 3

20-24 weeks later

Question 4

if the antibody screen is positive what must be done?

Answer 4

Identify and titer antibody

Question 5

what is tested for in prenatal monitoring?

Answer 5

• Ab titer

- Fetal Distress

Question 6

How do we measure fetal distress?

Answer 6

-aminocentesis
or
-Cordocentesis

Question 7

analyzes amniotic fluid bilirubin concentration at 450 nm

Answer 7

aminocentesis

Question 8

determines Hg, Hot, blood type, DAT of fetus

Answer 8

cordocentesis

Question 9

why do we preform a DAT from a Cordocentesis?

Answer 9

The DAT could indicate HDN because it should be Neg. Since babies don’t have antibodies formed yet and there for a positive DAT is being caused by moms antibodies binding to babies RBC’s.

Question 10

when can the fetus be determined to have the gene for the D antigen?

Answer 10

10-12 weeks gestation

Question 11

the relative concentration of all antibodies that are capable of crossing the placenta and cause HDFN is determined by______

Answer 11

antibody titer

Question 12

what is a critical titer?

Answer 12

a titer that is higher than 16

Question 13

T or F

The antibody titer method incudes the indirect antiglobulin phase using a reagent that is polyspecific.

Answer 13

F

-the reagent is mono-specific anti- IgG

Question 14

T or F

The antibody titer method uses enhancement media in order to visualize the rxns?

Answer 14

F

• the antibody titer does not use enhancement media

Question 15

How long is an antibody titer incubated for?

Answer 15

60 mins

Question 16

If an antibody titer reaches a trigger point of 32 what then should be preformed?
-when?

Answer 16

Color Doppler Middle Cerebral Artery Peak Systolic Velocity (MCA-PSV)studies
- 16 weeks gestation

Question 17

Non invasive method of assessing HDFN that uses ultrasound to look at the cerebral artery of the fetus

Answer 17

MCA-PSV

Question 18

what does the MCA-PSV measure? what does this indicate?

Answer 18

• the velocity of blood that is moving through the Cerebral artery of the fetus
• becomes faster with less RBC’s due to lysis

Question 19

if the DAT is posiive what should be done?

Answer 19

elution

Question 20

what characteristcs does a unit of blood need to have for a fetal transfusion?

Answer 20

• Fresh
• O-
• no mannitol
• CMV-

Question 21

Cell that are indicative of hemolytic Rxn’s

Answer 21

spherocytes

Question 22

what are the normal hemoglobin levels of Cordblood?

Answer 22

13.6-19.6g/dL

Question 23

when is prenatal monitoring preformed ?

Answer 23

after a positive antibody screen

Question 24

If an antibody titer is >16, then we will need to repeat at?

Answer 24

18-20 weeks gestation

Question 25

what are the main distinctions between ABO HDN and RH/ other HDN?

Answer 25

ABO HDN: -Spontaneously aggregates

-RBC acetylcholinesterase is decreased

Question 26

what is one method of detecting fetal cells in the mother?

Answer 26

Kleihauer-betke acid elution stain

Question 27

when should Postnatal Rh immune globulin (300ug) be administered?

Answer 27

with in 72 hours after delivery of Rh- positive child

Question 28

Rh immune Globulin that is administered:

• at 28 weeks gestation
• after abortion during first trimester
• following amniocentesis in second or 3rd trimester

Answer 28

antenatal Rh immune globulin

Question 29

when should we do an intrauterine transfusion

Answer 29

• MCA-PSV indicates anemia
• Fetal hydrops is noted on ultrasound examination
• Fetal hemoglobin level is less than 10 g/dL
• amniotic fluid delta OD 450nm result is high