APPENDIX II: DEFINITIONS IN HAEMOVIGILANCE

The following definitions and descriptions are used in the Australian National Haemovigilance Data Dictionary.

The transfusion of ABO incompatible product(s) resulting in an acute haemolytic transfusion reaction. Generally major ABO red blood cell mismatches result in significant morbidity or mortality, but minor incompatibilities may be innocuous and not result in harm. Incompatible platelet and plasma transfusions may or may not result in haemolysis and harm.

Haemolytic transfusion reactions (HTR) are clinically suspected if one or more of the following is present in a temporal association with transfusion:

• fever and a variety of other symptoms (including dyspnoea, hypotension, tachycardia, flank or back pain)
• inadequate rise in post-transfusion Hb level
• drop in Hb level (≥2 g/dl within 24 hours)
• rise in LDH (≥50% within 24 hours)
• rise in bilirubin, haemoglobinuria or decrease in haptoglobin levels.

It should be noted that adverse events attributed to transfusion of ABO incompatible products are included in the Incorrect Blood Component Transfused (IBCT) category. Such events could equally be described as acute haemolytic transfusion reactions, but the key failure is IBCT. Transfusion of ABO incompatible products to a patient is considered a 'sentinel event' and is also subject to other reporting channels outside of the National Haemovigilance Program.

Presents with one or more of the following during or within 4 hours of transfusion without any other cause such as haemolytic transfusion reaction or infection:

• fever (≥38^oC or change of 1^oC from pre-transfusion level)
• chills
• cold
• rigor
• other symptoms of discomfort.

One or more of the following without hypotension, and within 24 hours of transfusion:

• rash
• allergic dyspnoea (stridor, cyanosis, wheezing)
• angioedema
• generalised pruritis
• urticarial.

Allergic reaction with hypotension (drop in systolic BP ≥30mmHg) during or within 24 hours of transfusion or intractable hypotension or shock with loss of consciousness during transfusion, and without any indication of other cause.

Acute transfusion reactions occur within 24 hours of transfusion. They may have immune or non-immune aetiology.

Occurs between 1 and 28 days post-transfusion, and is the result of other atypical red blood cell alloantibodies.

Features respiratory distress, tachycardia, increased blood pressure, typical signs of cardiogenic lung oedema in the chest x-ray, evidence of a positive fluid balance and/or a known compromised cardiac status during or within 12 hours after transfusion.

TRALI may be immune or non-immune. Serological confirmation is not required for diagnosis. Clinical TRALI features:

• acute respiratory distress and
• diffuse bilateral lung infiltrations in the lung radiograph and
• occurrence during or within 6 hours of completion of the transfusion and
• no evidence of transfusion-associated circulatory overload (TACO).

Bacterial infection

Transfusion transmitted bacterial infection should be clinically suspected if:

• fever >39°C or a change of >2°C from pre-transfusion value and
• rigors and
• tachycardia >120 beats/min or a change of >40 beats/min from pre-transfusion value or a rise or drop of 30mmHg in systolic blood pressure within 4 hours of transfusion are present.

Possible transfusion transmitted bacterial infection:

• detection of bacteria by approved techniques in the transfused blood component but not in the recipient's blood or
• detection of bacteria in the recipient's blood following transfusion but not in the transfused blood component and no other reasons are ascertainable for the positive blood culture.

Confirmed transfusion transmitted bacterial infection:

• detection of the same bacterial strain in the recipient's blood and in the transfused blood product by approved techniques.

Viral infection

Following investigation, the recipient has evidence of infection post-transfusion and no clinical or laboratory evidence of infection prior to transfusion and either, at least one component received by the infected recipient was donated by a donor who had evidence of the same infection, or, at least one component received by the infected recipient was shown to have been contaminated with the virus. Reports should at least consider HIV, Hepatitis B, Hepatitis C and CMV.

Parasitic infection

Detection of the same parasite in the recipient's blood and parasite or specific antibodies in the donor blood.

TGVHD clinically features the following 1-6 weeks post transfusion, with no other apparent cause:

• fever
• rash
• liver dysfunction
• diarrhoea and
• cytopenia.

TGVHD is confirmed by GVHD-typical biopsy and genetic analysis to show chimerism of donor and recipient lymphocytes.

Clinically features purpura and thrombocytopenia within 12 days of transfusion. PTP is confirmed by the detection of platelet specific antibodies (usually anti-HPA-1a) in the recipient's blood, and detection of the antithetical antigen on the donor platelets, or by a positive platelet X-match.

A patient receives a blood component destined for someone else, or receives a component not to specification. For instance, an immune compromised patient may require irradiated cellular products but receive ordinary banked blood instead. No distinction is made whether or not harm was done.

Table 38: ANHDD definitions for contributory factors

Field Value	Explanatory note
None identified	No contributory factors have been attributed to the adverse event
Product characteristic	The product contributed to the reaction due to an inherent but not necessarily faulty characteristic (such as an allergic or anaphylactic reaction to a product; unknown significance of anti-HLA antibodies)
Transfusion in emergency setting	The transfusion was administered under emergency conditions
Deliberate clinical decision	The decision to transfuse was made with clinical forethought, and with due consideration of the possibility of a transfusion reaction
Prescribing/ordering	Event(s) during prescribing or ordering the product contributed to the transfusion reaction
Specimen collection/labelling	Event(s) during specimen collection or labelling contributed to the transfusion reaction
Laboratory (testing/dispensing)	Event(s) during laboratory pre-transfusion testing or dispensing of the product contributed to the transfusion reaction
Transport, storage, handling	Event(s) during the transport, storage or handling of the product contributed to the transfusion reaction
Administration of product	Event(s) during the administration of the product contributed to the transfusion reaction
Indications did not meet hospital transfusion guidelines	The clinical indications for transfusion did not meet hospital transfusion guidelines
Did not adhere to hospital transfusion procedures	The transfusion procedures did not adhere to hospital transfusion procedures
Other (specify)	Free-text field. Please specify the event(s) that contributed to the adverse transfusion reaction

Notes

1. Multiple entries allowed
2. At least one value to be returned