Antigens Flashcards
Which antigen is the receptor site for Plasmodium vivax?
Duffy, Fya or Fyb. Homozygous negative (Fya-/Fyb-) is common in blacks, rare in whites and prevents P.vivax infection.
How many random blood donors are e+?
98%
In what population is Jka-/Jkb- seen?
Polynesian (e.g. Hawaiian, Samoan, French Polynesian)
What are the typical properties of anti-M? Is it clinically significant?
Usually an IgM or cold IgG. Rarely reactive at body temperature. Rarely causes a hemolytic transfusion reaction.
What is Bombay phenotype?
Lack the H antigen. Make anti-A, anti-B, and anti-O. Can only receive blood from other Bombay.
Most common Rh group phenotype in Caucasians?
DCe overall and for Rh+ (42%, R1); DcE (14%, R2) is next for Rh+. For Rh-, dce (37%, r) is highest.
Most common Rh group phenotype in African Americans?
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-
Most common Rh group phenotype in Asian Americans?
70% are DCe (r1) 20% are DcE (R2). 0% of Rh- are big E+.
How many individuals are little k negative? (in other words K+/K+)
1 in 500 (0.2%), challenging to transfuse someone with anti-k
1 unit of pRBCs causes what Hgb and Hct increment in adults?
1 g Hgb or 3% Hct
To raise pediatric patient’s Hgb by 1 g/dL, give ___ cc/kg blood.
4 to 5 cc/kg. (Giving 10 cc/kg generally raises Hgb by 2 g/dL, 15 cc/kg by 3 g/dL).
How should you estimate the total blood volume in a pediatric patient? Adult patient?
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)
What is the max rate for FFP infusion? Risk of increased infusion rate?
1 ml/kg/min. Risk of hypocalcemia from citrate.
What is the dosing of FFP, and how much will the dose raise factor activities?
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%).
What is the typical volume of a unit of each: pRBCs, whole blood, FP, platelets, cryoprecipitate?
°° 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
What is the standard dosing of platelets? What is the expected platelet increment?
▶ 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
What does cryoprecipitate contain?
fibrinogen (150-300, averages 250 mg/bag), Factor VIII (8) Factor XIII (13), von Willebrand factor, fibronectin
What is cryoprecipitate dosing? By how much will it raise fibrinogen?
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
