Blood Bank Exam 2: Hemolytic Disease of the Fetus and Newborn (HDFN). Disease and Transfusion Information

what does HDFN stand for

Hemolytic Disease of the Fetus and Newborn

what is the basic definition of HDFN

destruction of fetal/neonatal RBCs by antibodies produced by the mother

where does the target antigen come from on the fetal RBCs and RBC precursors?

from the father

what Ab class crosses the placenta

IgG

what are the three examples of sensitizing events which could lead to HTR

transfusion

pregnancy

transplant

does a pregnancy have to be full term for it to be considered a sensitizing event?

no

what two events during pregnancy cause the sensitizing event (2)

during delivery

trauma to the abdomen during pregnancy

is HDFN usually a concern during a mothers first pregnancy?

no

is HDFN usually a concern during a mothers second (or later) pregnancy?

yes! since it is post sensitizing event

First pregnancy does not really matter

why does the mom make Ab to the baby? (4)

genetics

dose of fetal RBC introduced to mom

frequency of exposure

ABO incompatibility between mother and child

what are the three kinds of HDFN

ABO incompatibility

Rh incompatibility

other blood group incompatibility

what is the most common kind of HDFN

ABO incompatibility

how severe is ABO incompatibility

less severe than the other two kinds

what are the two antibodies that are the biggest concerns (severity wise)

#1: Anti-D

#2: Anti-K

what are the three requirements for it to be considered HDFN

THIS IS IMPORTANT SHE WENT OVER THIS A BUNCH

mom has formed an IgG Ab

mom lacks the corresponding antigen

baby has the corresponding antigen

what is the half life of maternal antibodies in the baby

25 days

what are the effects of HDFN on the baby

newborn is unable to conjugate bilirubin

unconjugated bilirubin builds up

causes permanent brain damage

what is the treatment for HDFN

phototherapy

exchange transfusion

what does phototherapy do

UV light breaks down bilirubin

what is exchange transfusion

use of whole blood to replace the neonates circulating blood

what is the purpose of exchange transfusion

removal of sensitized RBCs, maternal Ab, and unconjugated bilirubin

how do we detect HDFN before it happens?

maternal prenatal screening

cord blood (newborn) evaluation

what is done in the maternal prenatal screen

ABO Rh typing

antibody detection test

specialized testing

if a mother is RhD negative, are they a potential candidate for RhIG (rhogam)?

yes, depending on the baby screen

if a mother is RhD positive, are they a potential candidate for RhIG (rhogam)?

no

what specialized testing may be done on a maternal prenatal screen

antibody titration

genotyping for RHD

what is the purpose of antibody titration

to quantitate the amount of antibody

what do we look for when we genotype for RHD as part of a maternal prenatal screen?

partial D (risk for RhD immunization)

weak D (no need for immunization)

why do we look for RHD as part of the maternal prenatal screen?

guide RhIG (rhogam) prophylaxis and blood transfusion recommendations

what is evaluated as part of the cord blood (newborn) evaluation?

ABO Rh

DAT

what does DAT detect

in vivo sensitization (Ab on RBC) of the RBCs

how much should we wash cord cells before testing?

6 times

why do we wash cord cells 6 times?

to get rid of Whartons jelly

what is elution

the removal of bound Ab from sensitized RBCs

what is the purpose of elution

to remove maternal IgG from cord cells.

antibody identification is then done on these Abs which have been unbound from the RBCs

what are the two methods of elution

freezing (liu freeze)

acid (organic solvents/change in pH)

when should we do the liu freeze method of elution?

when there is an ABO mismatch

when should we do the acid method of elution?

Rh or other blood group mismatches

what should we do to confirm that an elution was successful?

test supernatant of the last wash

if it is negative it means you did a good job

what is reconstituted whole blood?

O RBCs and AB plasma

results in an antigen and antibody free whole blood product

when testing for exchange transfusion on the baby, whos blood should we test?

mom or baby

it a babies antibody detection test is negative, what does this mean about the kind of blood we can transfuse

we do not need to provide antigen negative blood

what are the blood selections considerations we have for baby exchange transfusions

fresh RBCs/whole blood (<7 days old)

how much blood is given in an exchange transfusion

volume twice that of the babies blood volume

what are three things the doctor may want from the blood used in an exchange transfusion

irradiated to disable donor WBCs

CMV negative

Hgb S negative