120.5

What is the blood group of red cells used in antibody screening and identification? Why?

Group O because they lack A and B antigen and therefore won't react ABO antibodies

List five reasons for preforming the IAT

To screen for unexpected antibodies in cases where a patient may need a transfusion. For example, elective surgery, labor and delivery, cancer patients, emergency surgery, burn patients, and pediatric patients

If the antibody screen is positive, what test is done to identify the antibody?

Antibody identification panel

If the autocontrol (AC) is positive, which test is done next?

DAT

What results on a panel of cells indicate the presence of a single antibody in the patient's serum?

Same agglutination strength reaction and perfect pattern match

What results on a panel of cells indicate the presence of two or more antibodies?

Variation in agglutination strength in single phase

Which class of immunoglobulin require enhancement for detection?

IgG

Which conditions or diseases cause a positive DAT?

Warm and cold autoimmune hemolytic anemia, HDFN, a drug-related mechanism, or an antibody reaction to transfused red cells

What procedure should be performed if the DAT is positive?

Elution

Describe the following grades in the agglutination in the gel testing: 0

Negative; no agglutination or hemolysis

Describe the following grades in the agglutination in the gel testing: 1+

Small agglutinates, free red cells in background

Describe the following grades in the agglutination in the gel testing: 2+

Medium agglutinates, clear background

Describe the following grades in the agglutination in the gel testing: 3+

Several large agglutinates, clear background

Describe the following grades in the agglutination in the gel testing: 4+

One solid agglutinate

List the antigens that are destroyed by proteolytic enzyme enhancement

Fya, Fyb, M, N, S, s

List the antigens that are enhanced by enzyme pretreatment

Kidd, Rh, Lewis, I

Which antibodies can be removed from sensitized red cells by dithiothreitol and 2-mercaptoethenol?

IgM
(also destroys Kell ANTIGENS)

Which immunoglobulin class can be removed from sensitized red cells by ZZAP reagent?

IgG
warm autoantibodies

What is the incubation time when using albumin enhancement? LISS enhancement?

LISS: 10-15 mins.
Albumin: 30-60 mins.

How is accurate Rh typing completed on a sample that exhibits a positive DAT?

Patient is usually e positive; test e negative panel cells to confirm specificity

How is donor blood selected after antibody identification?

Compatibility testing

Why are IgM antibodies not considered clinically significant?

They do not react in vivo

Why are IgG antibodies considered clinically significant?

They do react in vivo

List the substances that reduce the zeta potential to enhance agglutination?

LISS, BSA (albumin), PEG

Which antibody specificities are commonly seen for warm AIHA?

Rh antibodies, especially Anti-e

Which antibody specificities are commonly seen for cold AIHA?

anti-I, anti-H, anti-IH

Which antibody specificities are commonly seen for PCH?

autoanti-P (Donath-Landsteiner antibody)

If a patient has a positive DAT and the panel on the eluate is negative, what is the most probable cause of the DAT results?

Warm autoantibodies to medications and nonspecific binding proteins

If the antibody screen and auto control tubes agglutinate at the immediate spin phase and the agglutination disappears after 37°C incubation, what conclusion can be drawn and what should you do?

Cold reacting antibody; prewarm technique or REST adsorption

Which two procedures are useful in detecting anti-I?

Cold panel, cord blood cells

Which antibodies are best detected by enzyme enhancement?

Enhanced: Kidd, Rh, Lewis, I
Destroyed: Fya, Fyb, M, N, S, s

If you suspect a patient's serum has anti-Fya and another warm reacting antibody, how can the Duffy antibody be removed so that the other antibody can be identified?

Enzyme treatment to destroy Fya

Which antibodies are extremely labile and causes delayed HTR?

Kidd, Duffy

If all of the following cells of a panel are agglutinated except the AC, what is the patients antibody most probably directed against?

High incidence Ag-Antibody; Multiple antibodies; HTLA antibodies

Anti-D optimum temperature

37 degrees C

Anti-k optimum temperature

37 degrees C

Anti-Fya optimum temperature

37 degrees C

Anti-Jka optimum temperature

37 degrees C

Anti-M optimum temperature

RT

Anti-s optimum temperature

37 degrees C

Anti-Leb optimum temperature

RT

Anti-Xga optimum temperature

37 degrees C

Anti-Lub optimum temperature

RT

Describe the adsorption procedure and indicate its purpose.

Adding RBCs with known antigens to bind known antibodies in patient sample. This removes the antibodies you already know about so you can detect any remaining unknown antibodies

If a patient has cold AIHA and exhibits a positive DAT, what specifically causes in vivo red cells sensitization?

complement binding

Define elution

removal of antibody from DAT positive RBCs in a solution called an eluate which is tested for antibody specificity