Hemolytic Disease of the Fetus and Newborn (HDFN) Practive Flashcards

Vocabulary terms and definitions covering the etiology, diagnosis, testing, and treatment of Hemolytic Disease of the Fetus and Newborn (HDFN).

Hemolytic disease of the fetus and newborn (HDFN)

Also known as erythroblastosis fetalis, it is a condition where fetal or newborn red blood cells (RBCs) are destroyed by maternal immunoglobulin G (IgG).

Hydrops fetalis

A condition resulting from severe HDFN where edema occurs in the peritoneal and pleural cavities, which may lead to cardiac failure.

Kernicterus

Permanent brain damage that results if unconjugated bilirubin binds to tissues of the central nervous system.

Rh HDFN

The most severe type of HDFN, typically occurring when a D-negative woman is sensitized during a pregnancy with a D-positive baby.

ABO HDFN

The most common type of HDFN (1 in 150 births), occurring when a group O mother has a baby with group A or B blood.

Antibody Titration

A prenatal test used to determine if HDFN-related procedures are necessary; a rise by $2$ dilutions compared to baseline is considered significant.

Liley graph

A tool used to plot the change in optical density ($\Delta OD$) at $450\,nm$ against gestational age to determine the severity of HDFN (Zones 1, 2, or 3).

Lecithin-sphingomyelin (L:S) ratio

A test used to determine fetal lung maturity; the ratio should be greater than $2:1$ before inducing early labor.

Cordocentesis

A procedure where a fetal blood sample is taken for hemoglobin, hematocrit, and RBC genotyping, or for performing intravascular transfusions.

Blocking phenomenon

A cause of false-negative D testing where D-antigen sites are completely coated by maternal antibody.

Wharton’s jelly

A substance found in cord blood that must be washed away to prevent false-positive results during ABO forward grouping and DAT.

Rh immune globulin (RhIG)

A concentrate of anti-D given to D-negative mothers (standard dose $300\,\mu g$) at $28$ weeks’ gestation and within $72$ hours of delivery to prevent alloimmunization.

Rosette test

A qualitative screening method for fetomaternal hemorrhage that uses D-positive indicator cells to observe clumps under the microscope.

Kleihauer-Betke test

A quantitative test used to calculate the dose of RhIG based on the fact that fetal hemoglobin is resistant to acid elution while adult hemoglobin is not.

Phototherapy

A treatment using fluorescent blue light ($420$ to $475\,nm$) to convert bilirubin into isomers that are excreted in the bile.

Exchange Transfusion

The replacement of $1$ to $2$ whole blood volumes in a newborn to correct anemia and reduce bilirubin levels to between $18\,mg/dL$ and $20\,mg/dL$ to prevent kernicterus.