Antigens

Question 1

Which antigen is the receptor site for Plasmodium vivax?

Answer 1

Duffy, Fya or Fyb. Homozygous negative (Fya-/Fyb-) is common in blacks, rare in whites and prevents P.vivax infection.

Question 2

How many random blood donors are e+?

Answer 2

98%

Question 3

In what population is Jka-/Jkb- seen?

Answer 3

Polynesian (e.g. Hawaiian, Samoan, French Polynesian)

Question 4

What are the typical properties of anti-M? Is it clinically significant?

Answer 4

Usually an IgM or cold IgG. Rarely reactive at body temperature. Rarely causes a hemolytic transfusion reaction.

Question 5

What is Bombay phenotype?

Answer 5

Lack the H antigen. Make anti-A, anti-B, and anti-O. Can only receive blood from other Bombay.

Question 6

Most common Rh group phenotype in Caucasians?

Answer 6

DCe overall and for Rh+ (42%, R1); DcE (14%, R2) is next for Rh+. For Rh-, dce (37%, r) is highest.

Question 7

Most common Rh group phenotype in African Americans?

Answer 7

Dce overall and for Rh+ at 44% (R0); then DCe at 17% and DcE at 11%. dce (26%, r) is by far highest for Rh-

Question 8

Most common Rh group phenotype in Asian Americans?

Answer 8

70% are DCe (r1) 20% are DcE (R2). 0% of Rh- are big E+.

Question 9

How many individuals are little k negative? (in other words K+/K+)

Answer 9

1 in 500 (0.2%), challenging to transfuse someone with anti-k

Question 10

1 unit of pRBCs causes what Hgb and Hct increment in adults?

Answer 10

1 g Hgb or 3% Hct

Question 11

To raise pediatric patient’s Hgb by 1 g/dL, give ___ cc/kg blood.

Answer 11

4 to 5 cc/kg. (Giving 10 cc/kg generally raises Hgb by 2 g/dL, 15 cc/kg by 3 g/dL).

Question 12

How should you estimate the total blood volume in a pediatric patient? Adult patient?

Answer 12

Premature infant 100 cc/kg
Term neonate 85 cc/kg
Older Infant 75 cc/kg
Child 70-75 cc/kg
Adult 70cc/kg 
(But can be less for high BMI, tends to overestimate.  Tends to underestimate for underweight.)
Out of normal BMI:
BV = 70 / sqrt (BMI/22)

Question 13

What is the max rate for FFP infusion? Risk of increased infusion rate?

Answer 13

1 ml/kg/min. Risk of hypocalcemia from citrate.

Question 14

What is the dosing of FFP, and how much will the dose raise factor activities?

Answer 14

10-15 cc/kg in adults (usually 2-4 units), 10-20 cc/kg in peds.
Generally raises factor levels by 20% (15 to 30%).

Question 15

What is the typical volume of a unit of each: pRBCs, whole blood, FP, platelets, cryoprecipitate?

Answer 15

°° Packed red blood cells (PRBCs): 300 mL/unit
°° Whole blood: 450–500 mL/unit
°° Fresh frozen plasma (FFP): 250–300 mL/unit
°° Platelets: 40–50 mL/unit
°° Cryoprecipitate: 10–12 mL/unit

Question 16

What is the standard dosing of platelets? What is the expected platelet increment?

Answer 16

▶ Platelet random donor/equivalent unit: 50 cc
▶ Platelet pheresis bag: 300-400 cc (equiv of at least 6 random donor units)
▶ Dosing for platelets is usually 1 unit/5 kg (0.2 u/kg); some places do 1 unit/10 kg (0.1 u/kg)
▶ Increases platelet count by approximately 50,000 per uL

Question 17

What does cryoprecipitate contain?

Answer 17

fibrinogen (150-300, averages 250 mg/bag), Factor VIII (8) Factor XIII (13), von Willebrand factor, fibronectin

Question 18

What is cryoprecipitate dosing? By how much will it raise fibrinogen?

Answer 18

Generally 1 unit/10 kg, which will raise fibrinogen by 50 mg/dL.
Formula: units of cryo = [PV x (desired cryo - current cryo)/100)]/250 mg/unit