Blood Bank Rotation (Weeks 1 & 2)

Draw the pattern of IgM and IgG response to an antigen. Include the primary and secondary stimulation

Complete the table for Immunoglobulins

Papain cleaves IgG into 2 ________subunits

and 1 _______subunit.

What is the function of each subunit?

What type of bond holds the light and heavy chains together?

2 Fab and 1 Fc

Fc fixes complement

Fab is involved in binding antigens

Disulfide bonds

Prozone

excess antibody

Postzone

excess antigen

What is a complete antibody?

Give an example.

IgM is a complete antibody because it can react in saline at room temp on its own

What is an incomplete antibody?

How can it be detected? Give an example.

IgG is an incomplete antibody and requires assistance to cause agglutination

Can detect using IAT

What temperatures give the optimal activity for ABO antibodies? For Rh antibodies?

ABO=25˚C

Rh=37˚C

Which patient sample type cannot be used to detect complement fixation? Why not?

EDTA, because it chelates calcium and magnesium which inhibits complement

Which type of antibodies fix complement?

IgM and IgG subclasses 1, 2, and 3

A red top tube from a patient on renal dialysis would not clot after 1 hour because the patient was heparinized. What can be added to the tube to neutralize the heparin?

protamine sulfate

Specimen tubes for blood bank are good for _____days for most patients, but only 3 days for patients who have been ______________ or ___________ within the past three months

7

Transfused

Pregnant

Complete the chart on ABO frequency in a Caucasian population

An individual whose genotype is hh is classified as _________. This person makes naturally occurring anti-H.

What other naturally occurring antibodies will he make? If he requires a transfusion, what is the best blood type to provide?

Bombay

anti-A & anti-B

Blood from another Bombay individual

Place these blood types in the order of the highest to lowest concentration of H substance: A1 AB B O

O

B

A1

AB

What is the Immunodominant sugar and enzyme for group O individuals?

Fucose

L-fucosyl transferase

What is the Immunodominant sugar and enzyme for group A individuals?

GalNac

N-acetylgalactosaminyl tranferase

What is the Immunodominant sugar and enzyme for group B individuals?

Gal

Galactosyl transferase

How is a Cis-AB different from a Trans-AB?

Cis-AB has both alleles inherited on the same chromosome

What lectin can be used to determine if red blood cells are A1?

Dolichos biflores

It is common practice to add the liquid (serum or anti-serum) to the test tube before adding the red cells. What is the advantage of doing so?

So you can make sure that you added the serum to the tubes

For each of the following, identify the ABO typing discrepancy. Give a reasonable explanation. HINT: You can usually trust the 4+ reactions

How is acquired B acquired? What reagent can be used to prove that is the case?

Result of intestinal infection

Acetic anhydride

Rouleaux can make your reverse type look positive.What is rouleaux? How can it be dispersed?

It is the stacking of RBC's on one another due to proteins

Saline replacement to remove the serum

What does Ulex europeus detect?

anti-H

What does Dolichos biflores detect?

anti-A1

What is the universal blood donor? Why? What is the universal blood recipient?

O- because there are no naturally occurring antigens

AB+ is the universal recipient

What are the tests that are involved when a patient has a routine crossmatch ordered?

ABO

Rh

Antibody screen

What two components are added for a major crossmatch?

Patient serum

Donor red cells

What are the requirements for performing an electronic crossmatch?

Patient has been ABO typed at least twice, including current sample

No current or past history of antibodies

Is it a good idea to do a type and screen instead of a type, screen and crossmatch?

Ask your Blood Banker the advantage to doing just a type and screen

No. Must match compatibility of donor and patient and make sure patient has no antibodies.

Type and screen only is done when the patient is expected to get a transfusion soon and E-crossmatch is done

What error would an immediate spin crossmatch uncover?

ABO incompatibility

Cold antibody

How long does the blood bank keep a patient sample after the transfusion?

How long do they keep the donor "segments"?

Why should they keep them so long?

7 days

1 month

In case of transfusion reaction

The first thing we do when we receive an order for a crossmatch is to check the files. Why is this necessary?

What antibody is known to decrease and titer and then come roaring back and cause a transfusion reaction?

To see if there is a history of known antibodies

Kidds

After a unit of blood has been released, it must be transfused within______ hours. If the attending decides to hold the transfusion, the unit must be returned within ______ minutes, or before the unit temperature exceeds ______˚C.

4 hours

30 minuets

10˚C

What blood type are the cells used in a panel? Why is this important?

O no naturally occurring antibodies

What are the three "phases" of the antibody screen and panel?

IS

37˚C

AHG

If the check cells do not agglutinate, what can be the cause (give two reasons). What is the remedy?

Forgot the IgG or insufficient washing

Re-was or add IgG and re-spin.

What is the easiest way to know which antibodies are clinically significant?

They react at AHG and are listed first on the panel

Why do we reject hemolyzed samples from the Blood Bank?

Hemolysis masks antigen-antibody complex induced hemolysis for complement activation

What is the Rule of 3?

You have to have 3 cells positive for the suspected antibody and 3 cells negative for the suspected antibody

What four blood systems are all clinically significant?

Rh

Kell

Duffy

Kidd

If a patient has anti-e, how many units will you have to screen to find 1 that is compatible?

Possibly 100, 98% of the population is positive for e

Which of the following is low incidence, and which is high incidence... Kpa or Kpb.

Js a or Jsb?

Kpb and Jsb are high incidence

Define dosage. If an antibody shows dosage, how will the panel look?

Dosage describes how many copies of an antigen gene a cell has.

Rxns will be stronger with Homozygous cells and weaker with heterozygous

What 2 clues will help you identify that your patient has more than one antibody?

Variation in reaction strength

Reactions in multiple phases

Ficin is an enzyme that is used to treat a panel before adding the patient serum. Name 4 antigens that are destroyed by enzymes

N

M

S

Duffy

An antibody that is IgM can be destroyed by adding DTT. What is DTT and how does it destroy IgM?

Dithriothreitol

It cleaves disulfide bonds in IgM to destroy it

If you have a patient with anti-Lea and another antibody, how can you neutralize the anti-Lea to look underneath it?

Use plasma from a Lewis secretor to bind and remove anti-Lea

If you have a patient with anti-I, it will react with all panel cells. How can you look under it?

Pre-warm the sample

Is it ever acceptable to give Rh + blood to an Rh - person? What 2 conditions are necessary?

In case of emergency trauma or labor/delivery, as long as they don't already have an anti-D

You have a trauma patient who took 13 units of O negative blood. He is actually A positive and you'd like to switch back to his original blood type. Do you have to do anything special?

WELL, stay with O first of all.

If you must switch, check current sample for any anti-A or anti-B that could've been made from the massive transfusion of O blood against their own blood

What 3 genes are required for Lewis antigen production? What does each contribute?

Le gene

~codes for a glycosyltransferase, which adds L-fucose to a precursor

Se gene

~codes for secretion of ABO

Le(a & b)

~b+ determines if the lewis antigen is secreted

Why is Lewis a system rather than a blood group?

Secreted by tissue cells

Fill in the following Lewis secretion chart

How will red cells that are Le (a-b- ) phenotype when suspended in plasma containing Lea?

What about Le a and Le b ?

Will be positive

What is the most common phenotype producing Lewis antibodies?

Le(a-b+)

To what immunoglobulin class do most Lewis antibodies belong?

IgM

Will a person who is Le (a-b+ ) make anti Lea? Why or why not?

Persons whose RBCs are Le(a-b+) do not make anti-Le(a), because small amounts of unconverted Le(a) are present in their plasma and saliva

Can Lewis antibodies cause HDN? Why or why not?

No they are IgM and cannot cross the placenta

baby is Le- at first

A person who is Le(b) begins life as Le-. Then what happens?

They become Le(a) and then Le(b)

Complete the following antibody chart

Match the following blood group systems with their primry characteristics

Xga A. Found in the Mongolian population B. May be missed by some AHG reagents C. Alleles are Sm and Bua

Cartwright D. Inherited on the X

chromosome

Diego E. Yta and Ytb

Dombrock F. May cause severe transfusion

reactions and AIHA

Wright

Scianna

D

E

A

B

F

C

Why are homozygous cells preferred for antibody screening cells?

They have the most antigen on the cell surface and therefore have the best reactivity.

How does LISS enhance antibody detection? Albumin?

Reduces zeta potential around RBCs

Allows cells to come into closer contact

What is the advantage of monospecific AHG?

Production of antibody is longer lasting than the polyclonal source, since a hybridoma can live indefinetely

Blends provide fewer false-positive reactions as a result of anti-complement

What is the advantage of Polyspecific AHG?

Pooled donor antigen allows for a broader spectrum of reactivity

How will failure to adequately wash cells prior to adding AHG affect the reaction?

How will the Coombs control cells react in this case? If AHG is not present, how will Coombs control cells react?

Unbound antibody will still circulate

Negative check cells

What is the composition of an autocontrol? What can cause a positive autocontrol?

2 drops patient plasma, 1 drop patient RBC suspension

Autoantibody

How does a delayed transfusion reaction occur?

IgG is produced later, antibodies are undetectable for testing and then IgG is redetected after a re-exposure?

Why is knowledge of a patient's transfusion history and pregnancy history helpful in antibody identification?

Know what the patient might have been exposed to

When performing a panel how is the presence of a particular antibody in the patient's serum ruled out? Why is reaction grading important?

Examine the negative reactions to rule out antibodies by crossing off for antigens present using the rule of 3

Checks for dosage or multiple antibodies

How can antigen typing confirm an antibody identification?

Makes sure antigen doesn't exist, therefore correctly identifying why the antibody is there in the first place

What are the scoring values assigned to reaction strengths when performing an antibody titration?

4+=12

3+=10

2+=8

1+=5

When multiple antibodies are encountered in a patients serum, how many cells are necessary for confirmative testing?

Can the cells have more than one of the suspected complimentary antigens

3+ and 3- for each suspected antibody

No

When should the presence of an antibody to a high frequency antigen be suspected?

When almost all the screening cells in the panel are positive

What are the 3 most common cold autoantibodies?

anti-I

anti-H

anti-IH

In order to prove both are present, you need to find cells that are positive for one of the antigens and negative for the other. Does that make sense? Look at the panel image below. Imagine that the patient has an anti-C, and you think he also has an anti-K. What cell(s) will be helpful in figuring this out?

Cells 7 and 10

What is the major cause of transfusion fatalities?

Clerical error leading to ABO incompatibility

A recently transfused patient is scheduled for surgery on Friday.

Blood for a crossmatch for a

possible transfusion during surgery is drawn on Monday. Is this acceptable? Why or why not?

No, its been over 72 hours. The patient could've created new antibodies

What tests should be performed on a donor unit by the facility using the unit for transfusion?

ABO/Rh

What is a "clinically significant" antibody?

Antibody causing shortened RBC lifespan, or causing hemolytic transfusion reactions

Explain why Group O blood can be given to any blood group and a Group AB person can

receive any blood group.

Group O has no naturally occurring antigens and can therefore be given to anyone

Group AB has all naturally occurring antigens and can therefore receive from anyone

Differentiate between the immediate spin crossmatch and the antiglobulin crossmatch

Immediate spin is IS phase only and detects ABO incompatibility.

Antiglobulin goes to 37/AHG phases and uses enhancement media.

How will the autocontrol in the crossmatch react if a patient has an alloantibody?

An autoantibody?

Abnormal serum proteins?

Reagents are contaminated?

Negative

Positive

False positive

False positive