Which blood product has the highest incidence of Transfusion Related Acute Lung Injury (TRALI), Fresh Frozen Plasma (FFP), Packed Red Cells (PRC), or Pooled Platelets (PLT)?

Fresh Frozen Plasma Has the Highest Incidence of Transfusion Related Acute Lung Injury (TRALI)

Fresh Frozen Plasma (FFP) has the highest incidence of Transfusion Related Acute Lung Injury (TRALI) compared to Packed Red Cells and Pooled Platelets. 1, 2

Evidence for FFP as the Highest Risk Product

The risk of TRALI varies significantly among blood components, with FFP consistently showing the highest association:

• According to the AAGBI guidelines, the implementation of male-only plasma in component therapy began in the UK in 2003 specifically because FFP was identified as having the highest TRALI risk 1

• A comprehensive review in 2003 revealed that the TRALI risk per component was 6.9 times higher for FFP and 8.2 times higher for platelets than for red blood cells 2

• Studies have demonstrated that anti-HNA and anti-HLA antibodies, which are primary causes of TRALI, occur at higher frequency in multiparous women, making plasma from female donors particularly high-risk 1

Risk Reduction Strategies

The high incidence of TRALI associated with FFP has led to specific risk reduction strategies:

• Implementation of male-only plasma policies has resulted in significant reductions in TRALI cases:

  • In the UK, TRALI reports decreased from 36 in 2003 to 10 in 2006 after implementing male-only plasma 2
  • Highly likely/probable TRALI cases reduced from 22 in 2003 to just 3 in 2006 2
  • The risk of highly likely/probable TRALI due to FFP fell from 15.5 per million units to 3.2 per million units 2

• A before-and-after comparative cohort study showed that male-only FFP was associated with a 33% reduction in TRALI cases 3

Mechanisms of TRALI in Different Blood Products

The higher incidence of TRALI with FFP compared to other blood products can be explained by:

1. Antibody content: FFP contains higher concentrations of donor antibodies (anti-HLA and anti-HNA) that can directly trigger TRALI 1, 2

2. Volume considerations: FFP is typically transfused in larger volumes (approximately 300ml per unit) compared to other components 1

3. Donor characteristics: Historically, plasma from female donors who have been pregnant contains more antibodies that can trigger TRALI 1, 2

Clinical Implications

Understanding the higher risk of TRALI with FFP has important clinical implications:

• FFP should be avoided in patients without substantial bleeding 1
• When FFP must be used, pathogen-inactivated plasma or male-only plasma should be preferred 4
• For patients at high risk of fluid overload, special precautions should be taken when administering FFP 4

Relative Risk Comparison

While all blood products carry some risk of causing TRALI, the hierarchy of risk from highest to lowest is:

1. Fresh Frozen Plasma
2. Pooled Platelets
3. Packed Red Blood Cells

This is supported by multiple studies showing that FFP and platelet transfusions are more frequently implicated in TRALI cases than red blood cells 2, 5, 6.

In conclusion, the evidence clearly demonstrates that Fresh Frozen Plasma carries the highest risk of TRALI among the three blood products in question, with risk reduction strategies specifically targeting FFP administration having shown significant success in reducing TRALI incidence.