Blood Banking/Transfusions

Define the required tests that are performed on all donated blood:

ABO groups

1. Test the donor RBCs cells for antigens A and B

2. Test the donor plasma for antibodies to A and B

3. Donor should have antigens that are opposite to their antibodies

4. O blood lacks A or B antigens but has both Anti-A and Anti-B

5. AB blood has both A and B antigens, but lacks Anti-A and Anti-B

ABO groups testing

blood type, determining whether the person is an A, B, O, AB

universal donor

O - can be given to any ABO/Rh type

Define the required tests that are performed on all donated blood:

Rh type

• patient’s RBCs tested for D antigen
• Reagent Anti-D is added to RBCs
• If positive – patient is Rh Positive (has D antigen or D+)
• If negative – patient is Rh Negative (lacks D antigen or D-)

*D variants missed in routine Rh testing*

Rh type testing

your RH factor, the + or – (most of population is RH +)

Define the required tests that are performed on all donated blood: Ab screen

• Patient plasma mixed with a screen set of reagent Type O RBCs
• Expected result is a Negative Reaction
• Positive Reactions requires Antibody Identification Panel Workups
• Often the screening test requires Coomb’s Reagent

AB screen testing

1. screening patients plasma in vitro against 2-3 screening cells (RBCs) 

2. to see if patient’s plasma reacts with it. detects clinically significant blood group antibodies. If antibodies found, donor units lacking the corresponding antigen are identified prior to transfusion.

Define the required tests that are performed on all donated blood: Hep B surface Ag

1. positive in acute stage

2. earliest indicator of acute antigen infection

3. also indicates chronic infection

4. 12 weeks long!!!!

Define the required tests that are performed on all donated blood": Hep B core Ag

(6-14 wks) usually shows up positive w/ HBs Ag too

Define the required tests that are performed on all donated blood: Hep C virus

• Antibodies to Hepatitis C virus (Anti-HCV) = Past or current infection
• Hepatitis C Virus RNA (HCV RNA) = Current infection

Define the required tests that are performed on all donated blood: Syphilis (VDRL)

VDRL = Venereal Disease Research Laboratory Test
• High sensitivity test with high false-positive test rates
• True positives identified with confirmatory testing

Define the required tests that are performed on all donated blood: HIV 1 & 2

• Antibodies to HIV 1/2 (Anti- HIV 1/2)
• HIV-1 p24 Antigen
• HIV RNA
All stand for current infection with HIV

HIV 1 & 2 testing

1. HIV virus types which cause AIDS

2. HIV-1 most prevalent in US & Western Europe

3. HIV-2 most reported in West Africa

Define the required tests that are performed on all donated blood: HLTV 1 & HLTV 2

• Anti-HTLV-I/II antibodies = Past or current infection

• Retrovirus associated with adult T-cell leukemia and demyelinating neurologic disorders

Define the required tests that are performed on all donated blood: HIV Ag (HIV1 Ag)

testing for the antigen on the cell surface

Define the required tests that are performed on all donated blood: NAT

for West Nile Virus RNA

• available for other organisms like Babesa, Zika, 

• more sensitive than antigen testing

• used in PCR to detect viral load after infection but before seroconversion

Identify the required testing for whole blood recipients:

1. ABO group

2. Rh type

3. Antibody screen

4. Crossmatch for compatibility between donor’s cells and recipient’s serum

Describe the clinical indications for blood transfusions:

1. Malignant tumors (leukemias)

2. Cardiac surgical procedures

3. Surgical hip procedures

4. Anemias

5. Certain obstetric or gynecologic procedures or complications

6. Bone and joint diseases

7. Lung disease

8. Kidney disease or genitourinary system surgical procedures

9. Massive trauma

10. Liver disease

11. Certain blood dyscrasias

Describe the indications and clinical implications of testing for ABO group (type): 

done to prevent transfusion rxn w/ incompatible blood products.

also, 

• All blood donors and potential blood recipients must be tested for blood type to prevent transfusion with incompatible blood products. In general, patients are transfused with blood of their own ABO group because antibodies against the other blood antigens may be present in their blood serum.

***foundation/most important for all other pre-fusion testing***

Describe the indications and clinical implications of testing for Rh type (screen):

Done if Rh + blood given to an Rh negative person, also if Rh+ blood given to a person w/ an anti-D, to identify RhIG (Rhogam) candidates

• relates to the presence or the absence of the D antigen on the red cell membrane.

***second most important antigen in transfusion***

Describe the indications and clinical implications of testing for Rh Ab titer:

indicated in Rh-negative pregnant patients or those with a history of alloimmunization.

• clinical implication is to monitor for risk of hemolytic disease of the fetus and newborn (HDFN). Rising titers above a critical threshold indicate significant fetal risk and guide further monitoring and interventions.

Antibody titer

if its high or increasing = high risk for HDFN

Cross matching blood purpose

1. After all antibodies are identified, blood that is negative for the
   corresponding antigens is allocated

2. Segments from the units of blood are mixed with patient’s plasma,
   called a “full crossmatch”

Cross matching blood indications

As long as the crossmatch is negative, they are compatible

Cross matching blood common abnormalities

A POSITIVE CROSSMATCH

• When the patient’s plasma still reacts with antigen negative units

• May be due to rare antibodies (Select a new unit to test (if rare, should be easily avoided))

• May represent a flaw with your workup

• May be unavoidable

  • Autoantibodies bind to all RBCs, thus “Least Incompatible” Blood is given

  • Higher risk of transfusion reaction must be weighed with benefit of
    transfusion

Describe the clinical signs and symptoms of a transfusion reaction:

Fever, Chills

1. Chest, abdomen, or flank pain

2. Hypotension or HTN

3. Nausea

4. Dyspnea

5. Oliguria -very little of urine produced

6. Shock

7. back pain

8. feeling of heat/warmth along transfusion site

9. constricting chest & lumbar back muscles

10. facial flushing

11. Hemoglobinuria

12. oozing blood from wounds

13. Anemia

14. allergic rxns(local erythema, hives, itching

Indirect Coomb’s test according to description, indications, normal values, and clinical implications of positive results:

what it detects: anti-RBC antibodies in the serum or in other words free antibodies in serum

sample tested: serum

main use: prenatal screening, pre-transufsion crossmath

normal value: negative (no antibodies)

clinical implication of positive results: Patient has antibodies capable of binding RBCs → risk of hemolysis if exposed

Indirect Coomb’s test

"Potential risk" test → are there antibodies in the serum?

Direct Coomb’s test according to description, indications, normal values, and clinical implications of positive results.

what it detects: antigen-antibody complexes on the RBC membrane or in other words antibodies/complement already bound to RBCs

sample tested: Patient’s RBCs

main use: dx of hemolysis

normal value: negative (no coating of RBCs)

positive result means: Patient’s RBCs are already coated in their own body → ongoing hemolysis, hemolytic transfusion rxns, autoimmune diseases, drug induced

other causes of positive results

• HDFN in a baby if cord blood DAT is positive
• Transfusion reaction with hemolysis or antibody
• Autoimmune Disease
• Drug reaction
• Infection
• Not all positive DATs are clinically significant

Direct Coomb’s test

"Active problem" test → are RBCs already under attack?