The recently published Serious Hazards of Transfusion (SHOT) Report1 ? an independent, confidential inquiry into serious transfusion complications in the UK ? has revealed that Transfusion-Related Acute Lung Injury (TRALI) is the biggest killer of patients who receive blood. The number of incidents of TRALI that are being reported to SHOT have more than doubled in the last year.

TRALI occurs when patients undergoing minor and major operations are transfused with blood from a donor with a particular type of antibody that causes the recipient to have an allergic reaction. These types of antibodies are most commonly found in childbearing women but also in previously transfused male donors. Symptoms occur just hours after transfusion and, if not recognised and treated properly, TRALI can severely damage the lungs and, in some cases, result in death. Those patients who do not die can expect to spend time in intensive care as a result, occupying beds and consuming scarce resources unnecessarily.

The true size of the TRALI problem is unknown. Over the past six years, 103 TRALI cases have been reported to SHOT with 90 per cent of cases resulting in death or major harm. Worryingly, as SHOT relies upon voluntary reporting of adverse incidents, these figures could represent the tip of the iceberg. Prevalence figures from the US suggest one in 1,300 blood components transfused will cause the reaction ? over 3.4 million blood components are transfused in the UK each year.

SHOT itself highlights that the number of hospitals reporting adverse incidents is as low as 46 per cent. This is, in part, due to the fact that aawareness of TRALI is very low amongst doctors, who may confuse it with other clinical conditions.

Given that there is, currently, no way of knowing whether someone is likely to react to donated blood containing the TRALI-causing antibodies, anyone going into hospital for a routine operation could, theoretically, be seriously injured or even die as a result of this allergic reaction to the blood they may receive during the operation. Whatever the numbers actually are, each death and intensive care case represent a major concern because TRALI is an avoidable complication. This is, clearly, an unacceptable situation.

Of all the blood components used, SHOT identified single donor fresh frozen plasma (FFP) as the product most commonly associated with the development of TRALI. FFP is a component of blood, used in a number of life-threatening conditions where clotting factors are required, including liver transplantation, cardiac surgery and massive blood loss.

So, what can be done to prevent TRALI? There are three ways to reduce the risks:

The first is to screen for the TRALI-causing antibodies and eliminate carriers from donating. However, the medical community is not clear on exactly which antibodies are implicated in TRALI and, therefore, which ones should be screened for. Additionally, there are also concerns about the effect of losing a significant number of donors from the population given that there is already a shortage. Screening would take time to evaluate and implement.

The second method is to eliminate the plasma of female donors completely as women who have been pregnant represent the biggest source of TRALI-causing antibodies. However, the exclusion of women from donating plasma will take some time and, again, this method reduces the number of donors and does not eliminate the risk completely ? men may also carry these antibodies, and recent evidence suggests that factors other than these antibodies may also cause TRALI. Excluding women donors would also take time to evaluate and implement.

The third option is to use a form of pooled FFP which has been shown not to contain these TRALI-causing antibodies. This product, called Octaplas, has been readily available since it was licenced in 1998. There would be an increase in the cost associated with the provision of such a plasma but it has been shown nevertheless to be cost-effective. Currently less than five per cent of patients in the UK benefit from receiving Octaplas each year.

Patients receiving plasma in the NHS have the right to expect safe products, and deserve the right to be protected from unnecessary risks such as TRALI. In a society where compensation claims for Hepatitis C and other infections are costing the government many tens of millions and causing vilification in the media, TRALI now looms as the next big issue. However the risk of TRALI can, and should, be eliminated for transfusion patients at the earliest possible opportunity.