AB Detection & ID

Question 1

What is an antibody screen?

Answer 1

A test used to detect antibodies

Question 2

Who are antibody screens used for?

Answer 2

1. Transfusion paients
2. Pregnant Women
3. Patients who have had transfusion reactions
4. Blood and plasma donors

Question 3

What is the purpose of doing an IAT on a patient?

Answer 3

It’s used to detect unexpected antibodies in a patient’s plasma or serum using reagent RBCs (known).

Question 4

What are reasons for an unexpected antibodies to appear?

Answer 4

1. Found in addition to expected anti - A or Anti - B Ab
2. RBC stimulation from transfusion or pregnancy
3. May significant (IgG) or not significant (IgM)

Question 5

Naturally occurring antibodies form as a result of…?

Answer 5

Exposure to environmental sources (e.g. pollen, fungus, and bacteria), which have structures similar to some RBC antigens.

Question 6

Passively acquired antibodies appear as a result of…?

Answer 6

Produced in one individual and then transmitted to another via plasma - containing blood components (transfusion) or derivatives such as intravenous immunoglobulin (IVG).

Question 7

Presence of autoantibodies means…?

Answer 7

Complicates detection of clinically significant antibodies

Question 8

In blood banking we test “Blank” with “Blank”

Answer 8

Knowns (reagent RBC & reagent anti sera) with unknowns (patient serum and patient RBCs)

Question 9

What are the phases incorporated into IAT?

Answer 9

Immediate spin (IM), 37C, and AHG

Question 10

What phase in IAT can be done with or without potentiators?

Answer 10

The 37C incubation stage

Question 11

What stage in IAT is where washing is done?

Answer 11

AHG phase

Question 12

What is the purpose of Coomb’s Control Cells a.k.a. Check cells?

Answer 12

It’s used with negative reactions of AHG phase to ensure proper washing technique. The result of check cells should be positive. Negative is not good.

Question 13

Where do antigen sources come from in IAT?

Answer 13

Commercial red cells

Question 14

In IAT, where do antibody source comes from?

Answer 14

Patient’s serum/plasma

Question 15

What materials are used in auto control?

Answer 15

Tests a patient’s serum with their own RBCs

Question 16

If the auto control with a screen and its positive, what will need to be done?

Answer 16

May run a DAT (patient cells plus AHG) to detect in Vivo coating

Question 17

A auto control is positive, running AC and DAT will determine what about the antibodies?

Answer 17

If the antibodies are directed against the patient’s cells or transfused cells (allo- or autoantibody)

Question 18

How many phases are in DAT?

Answer 18

One phase (AHG)

Question 19

In DAT, what is the antigen source?

Answer 19

Patient’s RBCs

Question 20

In DAT, what is the antibody source?

Answer 20

Immunoglobulin attached to patient’s RBCs

Question 21

What does DAT tell you about the patient’s RBCs?

Answer 21

If IgG or C3 coating the patient’s RBCs in Vivo

Question 22

Describe the characteristics of a clinically significant antibody.

Answer 22

1. Usually IgG
2. Reacts best at 37 C and during AHG phase (IAT)
3. These antibodies are associated with hemolytic transfusion reactions (HTRs) and HDFN.

Question 23

In screening cells, which is more sensitive single or pooled donor group O cells?

Answer 23

Single donor O cells are more sensitive than pooled

Question 24

In screening cells which blood group is used and why?

Answer 24

O cells are used… will come back later. I forgot her explanation.

Question 25

What are your options to enhance an antigen - antibody reaction? Name 5.

Answer 25

1. Saline - may only enhance if incubation 4 long time
2. LISS - common choice
3. BSA (bovine serum albumin)
4. PEG, polyethylene glycol
5. Proteolytic enzymes - destroy some antigens

Question 26

Describe the use and limitations of saline

Answer 26

Use - Sensitive & cheap, and allows for shorter incubation time.
Limitations
1. Enhance cold autoantibodies
2. Some weak anti-K antibodies may be missed
3. Equal pans of plasma/serum and LISS are important
4. If ionic strength of a LISS procedure is altered, there is a decrease sing sensitivity of the test system

Question 27

What is the use of BSA and its limitations?

Answer 27

Use: Affects second stage of agglutination, reduces …TBC