Transfusion Transmitted Injuries Surveillance System
Project Progress Report 2001-2002

3. Results

3.1 Overall Results

From April 1, 2001 to June 30, 2002, a total of 99 adverse reactions were reported by participating provinces to the TTI Section, Health Canada. The highest proportion of reported reactions were “major allergic/anaphylactic (39%), followed by ”bacterial contamination" (24%) (Table 1).

3.2 Age and Sex

The largest proportion of adverse reactions (46%) occurred in patients aged 60 years and over, followed by those between 40-59 years (25%), and then those 0-19 years (19%). Males represented 58% of the reported reactions (Figure 1).

Figure 1: Adverse Transfusion Reactions by Age and Sex

3.3 Relationship to Transfusion

A high degree of association to transfusion was observed among the reported reactions, 80% being definite or probable (Table 2). Causality was assigned using the definitions listed in Appendix 3.

3.4 Severity of Outcome

There were minor or no sequelae following the occurrence of 57 (58%) adverse reactions, whereas 32 reactions (32%) were life-threatening and eight (8%) resulted in death (Table 3).

Table 3: Adverse Transfusion Reactions by Severity of Outcome

3.4.1 Deaths

The deaths were definitely associated with transfusion in two cases, probably in three cases, and possibly in three cases. The two deaths definitely associated with transfusion were due to a bacterial contamination of a platelet pool and an acute hemolytic reaction secondary to the transfusion of a wrong ABO red cell unit.

The three with a probable association were a case of TRALI, a case with an anaphylactic reaction and a cancer patient who developed severe hypertension during the transfusion of platelets.

For the three cases possibly associated with transfusion, the patients had been transfused with red blood cells:

No autopsy was performed on all these cases.

3.4.2 Bacterial Contamination

As shown, in Table 4a, there were 12 cases of definite or probable bacterial contamination. Most of these reactions were minor. Platelets were implicated in two thirds of these reactions. A variety of bacteria were isolated in the blood product culture, with predominance of skin contaminants.

Table 4a: Characteristics of Definite and Probable Cases of Bacterial Contamination

Twelve other cases of bacterial contamination were reported as possibly related to transfusion (Table 4b). In one of them the product culture was positive and the result of the recipient culture was unknown. According to the reporting province, the case was classified as possibly related to transfusion because it occurred within a time frame consistent with the administration of the blood product, but the event could also be explained by the recipient's primary or secondary diagnosis, treatment or by the administration of a drug or other agent. (This shows that there is some difference in the classification of bacterial contamination cases across the provinces). Two thirds of these cases were minor as well. Red blood cells (RBC) were implicated in most of these cases.

Table 4b: Characteristics of Possible Cases of Bacterial Contamination

3.5 Implicated Blood Products

The majority of the reported reactions (95%) were associated with the administration of fresh blood components. Of these, 54% were related to RBC; 23% to platelets and 18% to fresh frozen plasma (FFP) (Table 5a).

Table 5a: Adverse Transfusion Reactions by Suspect Fresh Blood Components

The reactions reported with the plasma derivatives (Table 5b) are known adverse effects of these products.

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