Transfusion Related Acute Lung Injury (TRALI)
Canadian Blood Services is working to further reduce the risk of Transfusion Related Acute Lung Injury (TRALI) - a serious reaction that can occur in some people who receive blood (not those who give blood). Most changes will be behind-the-scenes and should be seamless to our donors.
The following questions and answers are intended to help you better understand the issue.
What is TRALI?
TRALI is an uncommon but potentially fatal complication related to transfusion. Symptoms range from mild to life-threatening breathing difficulties. TRALI is generally believed to occur in one in 5,000 transfusions.
What causes TRALI?
There are some causes that we understand and some that we do not. However, most cases occur when antibodies in the blood of some donors react with incompatible proteins in some recipients following a blood transfusion. The result is a reaction that can cause lung damage to the person receiving the donated blood.
Who carries these antibodies?
The antibodies are most frequently found in women who have had multiple pregnancies, or people (men or women) who have had blood transfusions themselves. Carrying these antibodies is perfectly normal for these people and does not compromise their own health. It is only once the antibodies are "passed on" to someone with incompatible proteins through a blood transfusion that a reaction occurs in the recipient.
What blood products can trigger a TRALI reaction?
Various blood components carry different risks of TRALI. Since the antibodies are found in the liquid portion of the blood (plasma), high volume plasma components are thought to present the highest risk of causing TRALI.
High-volume plasma components include:
- Platelets collected through Apheresis
- Frozen Plasma (FP)
- Fresh Frozen Plasma (FFP)
- Concurrent Plasma (i.e., plasma collected during a platelet apheresis donation)
- Cryosupernatant Plasma (CSP)
- Whole blood derived platelets
- Fresh Frozen Plasma Apheresis (FFPA) (i.e., plasma collected via apheresis)
How common is TRALI?
Some medical professionals believe that TRALI is under-diagnosed and under-reported, making a true incidence rate difficult to calculate; however, it is generally believed to occur in one in every 5,000 blood transfusions. Further, the United States Food and Drug Administration (FDA) has reported TRALI to be among the top three causes of death related to transfusion in that country.
Don't you test all blood donations?
Yes, Canadian Blood Services tests every donation of blood and blood components for an array of infectious diseases. However, TRALI is not a disease; it is a reaction. It cannot be identified by a lab test.
What is Canadian Blood Services' position on reducing the risk of TRALI?
Canadian Blood Services is moving forward with continued TRALI reduction measures, which began in the fall of 2007 with the use of predominantly male plasma for the production of FP, FFP, Cryosupernatant and plasma used in platelet pools.
In March 2008 we proceeded to channel apheresis plasma donations into two streams: the first being male plasma to go to hospital recipients, and the second being female plasma to go to fractionation.
Starting July 20, 2009, women who have had previous pregnancies, including ectopic pregnancies, miscarriages and abortions, will not be permitted to donate platelets other than in special circumstances. This is because women who have been pregnant are at highest risk to develop the antibodies that may trigger a TRALI reaction in a transfused patient.
These measures are aligned to current best practices recommended by professional organisations, such as the American Association of Blood Banks, which advocate for countries to take steps to reduce the risk of TRALI in transfusion recipients.
Why is it safe to make a fractionated product from a woman's source plasma donation, but not safe enough for transfusion?
TRALI is rarely associated with fractionated products because female plasma is diluted by the pooling of plasma from thousands of other donations. Any harmful antibodies therefore become diluted by all the other plasma contained in that pool.
I have been pregnant--does this mean that I can no longer donate platelets?
Canadian Blood Services is taking preventative measures to help reduce the occurrence of TRALI in patients. To this end, platelet apheresis donors with a history of pregnancy-including ectopic pregnancies, miscarriages and abortions-will no longer be eligible to donate platelets except for special circumstances, such as: HLA or HPA Matched platelets, IgA deficient donors (the need for the rare component outweighs the small increase in TRALI risk associated with the particular donor), or severe platelet inventory shortages. Donors who successfully answer the Record of Donation questionnaire and meet current medical criteria will be allowed to donate.
I once had a blood transfusion, should I stop/avoid giving blood myself?
Depending on the reason for the transfusion, you will likely only be deferred for 12 months. If the transfusion was for the treatment of cancer, there is a permanent deferral because of the disease. There are other criteria that could lead to a lifetime deferral.
How do I know if my blood, plasma, platelets are risky to recipients?
The questions found in the Record of Donation are there help healthcare staff determine if a potential donor has any underlying condition or medical reason not to donate blood. But new pathogens and risks are discovered over time and require Canadian Blood Services and other blood centres to update the criteria for donating. All blood donations are also tested for a variety of conditions. If a test is positive the donor would be notified and the blood components would be discarded.