42/43: Blood Components - Kruse

Question 1

tests for antigens on the patients cells

Answer 1

forward typing

Question 2

tests for antibodies in the patients serum

Answer 2

backward typing

Question 3

Describe direct Coombs testing

Answer 3

reagent: anti-human immunoglobulin antibodies that binds to human IgG and IgM antibodies

Question 4

whats does direct coombs testing test for?

Answer 4

autoimmune hemolytic reactions

aka direct antiglobulin test DAT - tests for antibody mediated hemolysis

Question 5

What is an indirect coombs test?

Answer 5

aka indirect antiglobulin test

detects antibodies present in patient serum

Question 6

what is used for ABO testing, RH-D testing, and crossmatching of blood products?

Answer 6

indirect coombs test

Question 7

blood type refers to..

Answer 7

the antigen expressed by the red cells

A
B
AB - universal donor of plasma because no antibody to attack antigen
O (no antigen) - universal donor of RBC because no antigen for antibody to attack

Question 8

what is the bombay phenotype?

Answer 8

bombay phenotype: lacks H antigen

type O blood without H antigen will have anti-H antibodies in serum –> bombay phenotype pts need to receive blood from other bombay pts

Question 9

If mom is RhD antigen negative and she is exposed to Rhd antigen positive blood, she may form

Answer 9

anti-RhD antibodies (which can cross the placental barrier because IgG)

Question 10

absence of which minor RBC antigen is protective against malaria

Answer 10

duffy antigen

Question 11

special processing of RBCs

Answer 11

• leukocyte reduction ( reduces risk of CMV transmission in bone marrow transplant patients, does nothing for GvH)
• Washing (decreases risk of anaphylactoid reaction, particularly in IgA deficient patients)

Question 12

levels of Hgb that indicate anemia

Answer 12

less than 12.5 in females
less than 13.5 in males

go to 7 before need blood

Question 13

RBC transfusion triggers

Answer 13

• Hgb less than 7
• with active bleeding or active CVD less than 8
• general goal is to keep hemoglobin 7-9

Question 14

hematocrit is roughly

Answer 14

3x hemoglobin

Question 15

special cases - hemoglobin levels

Answer 15

• bleeding esophageal varices: keep pt as close to Hbg 8 as possible

Question 16

type and screen vs. type and cross **

Answer 16

type and screen = screens pts blood, does not prepare donor blood

type and cross = screens pts blood and cross matches donor blood for pt use

Question 17

contraindications to platelet transfusion

Answer 17

• heparin induced thrombocytopenia (increases rate of thrombosis, stop heparin)
• thrombotic thrombocytopenic purpura/ hemolytic uremic syndrome (accelerates disease process)

Question 18

Transfusion related infections

Answer 18

HIV
HCV
HBV
West Nile
CMV
Parasitic disease
*Bacterial infection (most common*** 1/2000 - 1/3000 mostly platelets)

Question 19

which transfusion has the highest rate of infection?

Answer 19

platelets **

Question 20

allergic transfusion reactions

Answer 20

preformed antibodies to donor plasma prtns

urticaria, pruritus, flushing, mild wheezing

give antihistamines

not typically dangerous, wait for symptoms resolve and complete transfusion

Question 21

anaphylactic transfusion reactions**

Answer 21

antibody to donor plasma prtns

hypotension, urticarial, bronchospasm, angioedema

rule out hemolysis, give epi IM**, anithistamines and corticosteroids

check pt for IgA deficiency*

use washed products in future

Question 22

febrile non-hemolytic transfusion reaction

Answer 22

due to preformed anti-WBC antibodies in pt

temperature rise greater than 1 degree celsius in first 1-2 hr of transfusion

give acetaminophen and minimize recurrence by giving pre-transfusion acetaminophen and using leukocyte reduced blood products

Question 23

delayed hemolytic transfusion reaction

Answer 23

occurs 1-2 wks after transfusion

fever, jaundice, falling hgb

repeat type and screen to look for new antibody formation, redo transfusion

Question 24

acute hemolytic transfusion reaction

Answer 24

preformed antibodies incompatible attack donor product antigen

chills, fever, hypotension, back pain, DIC

aggressively treat with IV fluids

use pressors if needed

keep good urine otuput

Question 25

TACO transfusion associated circulatory overload

Answer 25

hydrostatic fluid overload

essentially a decompensated CHF caused by transfusion

dyspnea, tachypnea, JVD, peripheral edema

prevent with slow transfusion rates and treat with diuretics

Question 26

TRALI transfusion related acute lung injury

Answer 26

massive capillary leak in the pulmonary vasculature

hypoxemia, transient leucopenia, bilateral pulmonary edema

occurs w/i 6 hr transfusion

5-20% mortality, most common with whole blood transfusions