What is the primary concern of pre-transfusion compatibility testing?

- To ensure donor units and recipient units are compatible

- To find the best match where the donor cells won't be destroyed by the recipient and that the transfusion has the best possible outcome

What are four common reasons that transfusion units are requested?

1. Surgical Procedures

2. Acute, unexpected blood loss

3. Chronic Anemia Correction

4. Special needs: oncology or dialysis

Approximately how many units are infused a year?

30,000,000 (FDA report from 2006)

What is the breakdown of each transfused component by percentage?

- Almost 1/2 Red Blood cells (49%)

-Apheresis Platelets (30%)

- Plasma products (13%)

Other (8%)

Cryoprecipiate (for fibrinogen)

Anti-thrombin

Immune globulin (why?)

Clotting factors - VIII, IX (recombinant now)

- Granulocytes (last resort)

- Whole blood (really ever still used?)

What is a transfusion of cryoprecipitate used for?

Fibrinogen

Name 7 causes of transfusion related fatalities

1. TRALI (48%)

2. HTR (non-ABO related) (16%)

3. HTR (ABO related) (10%)

4. Microbial infection (12%)

5. TACO (11%)

6.Anaphylaxis (3%)

7. Other (1%)

(Graft vs. Host disease, therapeutic plasma exchange error, hypotensive reaction)

What does TRALI stand for?

Transfusion-Related Acute Lung Injury

What is a major cause of TRALI?

Plasma products area  major cause of TRALI

What does TACO stand for?

Transfusion Associated Circulatory Overload

What antibodies are most responsible for HTRs?

ABO group

What is a major cause of preventable transfusion-associated fatalities?

Clerical errors

(50% in 2002 - 20% in 2007)

In 2002, what was more likely: a fatal transfusion error or transmission of HIV via transfusion?

Fatal transfusion error is 50-100 times more likely

What are the six steps of required testing for pre-transfusion testing?

1. Proper Patient ID and sample collection

2. ABO and Rh test

3. Historical Record Check

4. Ab Screen (& ID abs if necessary)

5. Management of previously identified antibodies

6. Crossmatch 

When a recipient recieves a sample, what are the two identifications that have to be made?

At what times should these ids be made?

- Patient and samples both need to be identified

-Full Name and Patient Id must be checked at a minimum

Times are: - At the time of collection

- When lab testing is done

- Time of transfusion

A new sample should be requested if there is any doubt about...

1. Id

2. Time/date of draw

3. Quality of draw

How old should the sample be?

As fresh as possible

No older than 72 hours if pregnant or tranfused in the last 3 months

What should happen to the remainder of a sample after it has been transfused?

It should be retained and stored for 7 days

(In case of delayed reaction)

Where should determination of ABO and Rh type of the recipient be done?

At the site where the transfusion will be done

Do the donor units need to be retyped before a transfusion?

If so, which types?

Yes, the type testing should be repeated for the specific blood and compatible blood 

Why is it required by law to keep and access recipient records?

Recipients are the ones most likely to react to a mistyped or badly matched donor

Can the antibody screen (and identification if necessary) be done in advance of transfusion?

Yes, in advance or at the time of transfusion

What must an antibody screen (and Id) be able to detect?

Clinically significant unexpected antibodies

In what percentage of the general patient population do clinically significant unexpected antibodies occur? 

~0.7 - 1.7 %

Why is an antibody screen and Id required?

To determine if antigen negative blood is needed

What antigens are always significant?

ABO

Rh

Kell

Duffy

Kidd

S, s, U

P

What is the definition of a major crossmatch?

Donor cells and recipient serum

What is the definition of a minor crossmatch?

donor serum and recipient cells

(not done frequently any more - do antibody screen instead)

(also don't really use whole blood which contains donor serum/)

What is the purpose of a crossmatch?

To ensure the cells from the donor will survive in the recipient and cause no damage

During the crossmatching procedure - where does the donor serum and plasma come from in the lab?

Closed segments

What percentage of antibodies does an antibody screen detect?

Is immediate spin enough for an antibody spin?

IS, 37 degrees, AHG

When can an electronic match be used?

To take the place of an IS cross match

What is the sign of a compatible crossmatch

No agglutination/hemolysis

What are some causes of incompatibility?

- Incorrect ABO grouping of patient or donor

- Patient' sserum has an ABO antibody

- Donor units have a positive DAT

- Alloantibody in patient's serum reacting with antigens on donors cells and screening cells

- Both an autoantibody and alloantibody present in the patient's serum

-Imbalance in patient's serum (plasma expanders, caprylate antibodies, contaminants) 

What happens when a donor unit if found to be compatible?

The unit is tagged for possible use by that patient

- and - 

Its important that before a unit is released the identification of both the recipient and the donor be maintained with the unit (tracking) 

What are the four promises a blood can not make about units being transfused?

1. Can not guarantee normal survival of donor cells

2. Can not prevent sensitization

3. May not avoid delayed transfusion reaction

4. can not completely prevent disease transmission

What three things should happen if it is necessary to release uncrossmatched blood in an emergency?

1. A physician must sign a release assuming all responsibility

2. A sample must be taken and tested while transfusion is underway

3. The unit selected should be O neg or else type specific if there is time to accomplish that

What is necessary for an intrauterine transfusion or a transfusion of an infant under 4 months?

The donor should be compatible with maternal serum

(O neg is often used)

What is a massive tranfusion?

When an entire blood volume is replaced in 24 hours

How many units does it take for a massive transfusion?

It takes 8-10 units to replace the entire blood volume of the human body

For a massive tranfusion - type specific blood can be released....

After IS X match

What should be done if a transfusion is needed but no compatible blood can be found?

Recipient should recieve a test aliquot of a unit and a blood sample should be collected from the opposite arm 30 minutes later

(The blood may still survive to do its job even if it didn't pass crossmatch)

When double checking type - what tests should be done?

Just the forward and Rh is okay to mistake?

What is transfusion therapy?

Transfusion of the specific blood component needed by the patient

What benefit does a donation of RBCs give to a patient?

Increased O2 carrying capacity

What benefit does a donation of platelets give to a patient?

Homeostasis

What benefit does a donation of plasma give to a patient?

Plasma proteins / Coagulation proteins

What blood components are commonly transfused?

- Whole blood (not so much any more)

-Red Blood Cells

(RBC's w/ adenine-saline added)

(Pheresis)

(deglycerolyzed - washed)

(Leukocyte reduced)

- Platelets

(Pooled)

(Pheresis)

(Leukocyte reduced)

(Pheresis - leukocyte reduced)

- Granulocytes

(Pheresis)

- Plasma

(Fresh frozen)

(Thawed)

(Cryoprecipitate reduced)

- Cryoprecipitate

What is the Hct of whole blood and under what circumstances is it given?

About how much is given and what are the risks?

By how much will the hemoglobin/Hct  be increased?

40%

Symptomatic anemia with large volume deficit - Replace RBC mass and volume (massive bleeding)

550-600ml

Volume overload, ABO requirement

1-1.5 g/dl / Hct ~3%

What is the Hct of RBC pheresis and under what circumstances is it given?

About how much is given and with what additive solution?

By how much is the Hct improved?

Hct 55-70%

Symptomatic anemia

~330 ml of packed red cells

Additive solution AS-1

(~250ml, Hct 70-80% w/o additive solution) 

Hct goes up by ~3%

What is the Hct of deglycerolyzed, washed RBCs and under what circumstances is it given?

How many of the RBCs survive the freezing process?

How soon must it be transfused?

About how much is given?

Hct 75%

Symptomatic anemia

Severe allergic reactions

80%

2 weeks

180 ml

How many WBS are in leukocyte reduced red blood cells and under what circumstances are they given?

What are the benefits of leukocyte reduction?

Less than 5 x 10^6

Symptomatic anemia

Immunosuppressed or immunocompromised

Febrile reactions due to leukocyte antibodies

Reduce CMV, EBV, HIV, HTLV transmission

Reduce HLA alloimmunization

Reduce transfusion associated graft vs host disease (TA GVHD)

WBCs are not our friends

About how many platelets are in a unit of pooled platelets and under what circumstances are they given?

About how much is given?

How many units can be given?

Greater than or equal to 5.5 x 10^10 platelets/unit

Bleeding due to thrombocytopenia or platelet function abnormality

Prevention of bleeding from marrow hypoplasia 

About 40-70 ml (with coagulation factors)

Can use singly or up to 6 units (=1 adult dose)

About how many platelets are in a unit of platelet pheresis and under what circumstances are they given?

About how much is given?

Greater than or equal to 3.0 X 10^11/unit

Same as platelets

Crossmatched and/or HLA matched

100-500 ml

Why are leukocyte reduced platelets given?

Prevention of febrile reaction

Prevention of HLA-alloimmunization

About how many granuclocytes are given in a unit of granulocyte pheresis and under what circumstances is it given?

Greater than or equal to 1.0 x 10^10 PMN/unit

Neutropenia with infection unresponsive to appropriate antibiotics

What is the important component of fresh frozen plasma and under what circumstances is it given?

All coagulation factors

Deficiency of labile and stable plasma coagulation factors

TTP

What is important about the composition of thawed plasma and under what circumstances is it given?

Reduced factors V and VIII

Deficiency of stable coagulation factors

TTP

What is important about the composition of cryoprecipitate reduced plasma and under what circumstances is it given?

Reduced fibrinogen, factors VIII, XIII, and vWF

TTP, HUS

What is important about the composition of cryoprecipitate and under what circumstances is it given?

Fibrinogen, vWF, factors VIII, and XIII

Hypofibrinogenemia

Factor XIII deficiency

How long should a patient have to wait for a whole blood transfusion?

Transfusion should be delayed until it is absolutely necessary

What level of Hgb is elibible for a whole blood transfusion?

< 7 g/dl

In most cases, what is the red cell product of choice?

Packed cells

At room temperature - what is the upper limit for a red blood cell unit to be transfused?

Not above 4 hours

How long are RBCs good for if kept at the right temperature?

42 days

Normally for red blood cell transfusions testing includes...

Compatibility Testing

What should happen during the initial portion of a transfusion?

It is given slowly so the patient can be observed for acute reactions

After that the rate can be increased as long as the patients circulatory system is able to tolerate it

What can be an incompatability problem with plasma?

Proteins and antigens that have been mismatched

ie - if a patient is IgA deficient will react strongly to IgA

Ovr what frame of time should packed red blood cells be given to older people?

The unit should be spilt so that each half can be given over the usual 4 hour period

What is glycerol used for with RBCs?

What must be done to glycerolized RBCs once they have been thawed?

A cryoprotectant

Units must be washed after thawing and prior to transfusion

In what three cases are red blood cells frozen and glycerolized?

1. Rare blood types (rare donor negative units)

2. history of allergic transfusion reactions (serum proteins washed away)

3. Autologous units

With what are RBCs washed?

What is washed away?

What types of patients require washed cells?

Saline

Plasma Proteins

- Patients with a history of allergic reactions

- Rare patients who have IgA deficiency and have developed anti-IgA

What are four indications for platelet transfusion?

1. Thrombocytopenia

2. Chemotherapy for malignancy (decreased production, <10,000/uL)

3. Disseminated intravascular coagulation (increased destruction, <50,000/uL)

4. Massive trasfusion (platelet dilution, <50,000/uL)

What is a platelet dose for an adult? 

By how much is the platelet count increased in a 70 Kg adult?

How long can platelets be stored?

4-6 pooled units or 1 aheresis unit per adult

20-60 x 10^3/ul

5 days (closed system)

4 hours if pooled or in an open system