Heme/Onc

Question 1

Where does hematopoiesis happen?

Answer 1

Starts in secondary yolk sac
Liver takes over around week 5-6 (primary site till week 22)
Bone marrow takes over between weeks 8-19, primary site after week 22

Question 2

Hb electrophoresis in sickle cell?

Answer 2

Hb S and Hb F, no Hb A

Question 3

Protein abnormality in sickle cell?

Answer 3

Valine for glutamic acid at position 6, abnormal beta globin

Question 4

Most common hemoglobinopathy in the world and which chromosome is the abnormality on?

Answer 4

Hemoglobin E, chromosome 11

Abnormality leading to decreased production of beta globin chains

Question 5

When should a NBS be repeated if altered by a transfusion?

Answer 5

2 months after last transfusion

Question 6

How many mL of fetal blood in 1% HbF

Answer 6

50 mL

Question 7

What causes false negative KB test results?

Answer 7

Blood group incompatibility leading to accelerated clearance from maternal circulation

Question 8

Bone marrow with absent erythroid precursors is seen in which syndrome?

Answer 8

Diamond Blackfan

Also with triphalangeal thumbs

Question 9

Etiology of Fanconi anemia

Answer 9

Autosomal recessive, chromosomal instability with breakage. It can be tested with mitomycin C

Question 10

Which virus causes erythroid aplasia

Answer 10

Parvovirus B 19

Question 11

What type of blood incompatibility is associated with more severe disease with subsequent pregnancies?

Answer 11

Rh incompatibility.

ABO is NOT more severely affected with subsequent pregnancies, and may occur in the first

Question 12

When is RhoGam administered?

Answer 12

28 weeks and delivery, after any invasive procedures, and within 72 hours of delivery of Rh-positive infant

Question 13

How is monitoring for fetal anemia done?

Answer 13

Monitor middle cerebral artery peak systolic velocity by ultrasound
Severe risk if MCA greater than 1.5 multiples of the median

Question 14

Which minor blood group antigens do not cause hemolytic disease?

Answer 14

Lewis antigen (does cause positive Coombs)
Anti I
Anti Fyb

Question 15

Which antigens cause most severe expression of hemolytic disease?

Answer 15

Rh, followed by Kell

Duffy (Fya) and Kidd also but have low overall prevalence

Question 16

Most frequently inherited enzyme defect?

Answer 16

G6PD deficiency

Question 17

Most common complication after an exchange transfusion?

Answer 17

Thrombocytopenia, because the whole blood doesn’t contain platelets

HypOcalcemia may be seen (due to preservatives)
Hypotension may occur during the procedure

Question 18

Formula to calculate blood volume exchanged?

Answer 18

(Observed Hct - desired Hct)/observed Hct x infant’s blood volume

Question 19

What is an infant’s blood volume?

Answer 19

80-100 ml/kg
Term closer to 80/kg
Preterm closer to 100/kg

Question 20

Most commonly implicated antigen in whites in NAIT?

Answer 20

HPA-1a. Also known as PLA1

HPA4b in other races

Question 21

Vitamin K dependent factors?

Answer 21

Factor 2, 7, 9 and 10

Question 22

Syndromes with an increased risk of congenital leukemia?

Answer 22

Fanconi’s anemia, Diamond-Blackfan syndrome, trisomy 21

Question 23

Most common solid tumor in the neonatal period and its major site?

Answer 23

Teratoma, 50% in sacrococcygeal region

Question 24

What is hemoglobin Barts?

Answer 24

4 gamma globin chains - tetramers

Question 25

What is hemoglobin H?

Answer 25

Beta globin tetramers

Question 26

Diagnostic testing for hereditary spherocytosis?

Answer 26

Flow cytometric osmotic fragility test and eosin 5 maleimide (EMA) test (this is preferred now, osmotic fragility requires a lot of blood)

Question 27

Drugs that induce indirect hyperbili?

Answer 27

Ceftriaxone, sulfonamides, indomethacin

Question 28

Difference between neonatal alloimmune and autoimmune thrombocytopenia?

Answer 28

Autoimmune: maternal and infant’s platelets are low. Mother has autoimmune disorder, antibodies destroy both mom’s and infant’s platelets

Alloimmune: infant’s platelets are low, mother’s are normal.

Question 29

Hallmark lab findings with TMD?

Answer 29

Leukocytosis with neutrophils
Thrombocytopenia
Blasts on blood smear

Chemotherapy does not prevent the occurrence of leukemia

Question 30

When does peak iron transfer in the fetus occur?

Answer 30

After 30 weeks gestation

Question 31

What is the total body iron content in a term infant?

Answer 31

75 mg/kg - about 80% is in hemoglobin

Question 32

How does heparin work? Most important factors inhibited by heparin?

Answer 32

Antithrombin III mediated inactivation of coagulation factors. Most importantly factors Xa and IIa

Question 33

Factors responsible for subtherapeutic heparin levels/resistance?

Answer 33

Inadequate concentrations of antithrombin
Increased clearance of heparin
Increased binding of heparin to plasma proteins
Increased concentration of fibrinogen, or factor VIII

Question 34

How is heparin cleared?

Answer 34

1. Degradation in epithelial cells and macrophages

2. Renal clearance (Neonates and young infants have faster clearance of heparin than do children and adults)

Question 35

Assays used to identify and quantify fetal blood in maternal circulation?

Answer 35

Kleihauer-Betke assay and flow cytometry.

Question 36

Basis of Kleihauer-Betke test?

Answer 36

difference in acid solubility between hemoglobin A and F

HbA becomes ghost cells

Question 37

How do you prevent transfusion associated graft versus host disease?

Answer 37

Irradiation (also reduces shelf life to 28 days)

Question 38

What does leukoreduction prevent?

Answer 38

Decreases febrile nonhemolytic transfusion reactions by 60% 
Decreases viral (cytomegalovirus) transmission, and HLA alloimmunization.