John A. J. Barbara

Serious hazards of transfusion (SHOT) initiative: analysis of the first two annual reports

Abstract Objective: To receive and collate reports of death or major complications of transfusion of blood or components. Design: Haematologists were invited confidentially to report deaths and major complications after blood transfusion during October 1996 to September 1998. Setting: Hospitals in United Kingdom and Ireland. Subjects: Patients who died or experienced serious complications, as defined below, associated with transfusion of red cells, platelets, fresh frozen plasma, or cryoprecipitate. Main outcome measures: Death, “wrong” blood transfused to patient, acute and delayed transfusion reactions, transfusion related acute lung injury, transfusion associated graft versus host disease, post-transfusion purpura, and infection transmitted by transfusion. Circumstances relating to these cases and relative frequency of complications. Results: Over 24 months, 366 cases were reported, of which 191 (52%) were “wrong blood to patient” episodes. Analysis of these revealed multiple errors of identification, often beginning when blood was collected from the blood bank. There were 22 deaths from all causes, including three from ABO incompatibility. There were 12 infections: four bacterial (one fatal), seven viral, and one fatal case of malaria. During the second 12 months, 164/424 hospitals (39%) submitted a “nil to report” return. Conclusions: Transfusion is now extremely safe, but vigilance is needed to ensure correct identification of blood and patient. Staff education should include awareness of ABO incompatibility and bacterial contamination as causes of life threatening reactions to blood. Key messages Blood transfusion, while extremely safe, has several potentially fatal hazards All staff handling blood should be aware of the importance of correct identity of sample, patient, and blood bag at all stages Resources should be directed to evaluation of methods for improving identification of patients Acute fever or collapse during or after transfusion may be due to ABO incompatibility or bacterial contamination Microbiological complications of transfusion accounted for a minor component of all reports

Estimation of the risk of hepatitis B virus, hepatitis C virus and human immunodeficiency virus infectious donations entering the blood supply in England, 1993–2001

Background and Objectives The frequency of hepatitis B virus (HBV), hepatitis C virus (HCV) or human immunodeficiency virus (HIV) infectious donations entering the blood supply in England is too low to monitor using observational studies. The expected frequency of infectious donations can be estimated and these estimates may be used to contribute to monitoring of blood safety and used in the design of strategies to decrease the risk of transfusion‐transmitted infections.

Relative values of the interventions of diversion and improved donor-arm disinfection to reduce the bacterial risk from blood transfusion

Background and Objectives  The aim of this study was to demonstrate the efficiency of diverting the initial 20‐ml donation from the collection bag and of an improved donor‐arm disinfection procedure in reducing bacterial contamination in blood.

Prospective investigation of transfusion transmitted infection in recipients of over 20 000 units of blood

Abstract Objectives: To follow up recipients of 20 000 units of blood to identify any transmissions of infections through blood transfusion. Design: Follow up study of recipients of transfusion. Setting: 22 hospitals in north London. Participant: Adult patients who had recently been transfused. Main outcome measures: Patients had further blood samples taken at 9 months that were tested for markers of hepatitis B and C and HIV and human T cell leukaemia/lymphoma virus type I or II (HTLV) infections. Recent infections were distinguished from pre-existing infections by comparison with blood samples taken before transfusion. Results: 9220 patients were recruited, and 5579 recipients of 21 923 units of blood were followed up. No transfusion transmitted infections were identified. The incidence of transfusion transmitted infections was 0 in 21 043 units (95% confidence interval for risk 0 to 1 in 5706 recipients) for hepatitis B; 0 in 21 800 units (0 to 1 in 5911 recipients) for hepatitis C; 0 in 21 923 units (0 to 1 in 5944 recipients) for HIV; and 0 in 21 902 units (0to 1 in 5939 recipients) for human T cell leukaemia/lymphoma virus. Three patients acquired hepatitis B during or after hospital admission but not through transfusion; 176 (3%) had pre-existing hepatitis B infection. Sixteen (0.29%) patients had hepatitis C, and five (0.09%) had human T cell leukaemia/lymphoma virus. Conclusions: The current risk of transfusion transmitted infections in the United Kingdom is very small, though hospital acquired infections may arise from sources other than transfusion. A considerable proportion of patients have pre-existing infections.

Evaluation of donor arm disinfection techniques.

To validate a standardized optimal national procedure for donor arm disinfection.

Evaluation of the 3D BacT/ALERT automated culture system for the detection of microbial contamination of platelet concentrates.

Summary Bacterial transmission remains the major component of morbidity and mortality associated with transfusion‐transmitted infections. Platelet concentrates are the most common cause of bacterial transmission.

Documented cases of post-transfusion malaria occurring in England: a review in relation to current and proposed donor-selection guidelines.

Background and Objectives  Although uncommon, five cases of transfusion‐transmitted malaria have been documented in England over the last 20 years. With the reappearance onto the market of high‐quality malaria antibody assays, and by utilizing the results of analysis of these five cases, it has been possible to review the donor malaria‐deferral guidelines.

Evaluation of the BacT/Alert automated blood culture system for detecting bacteria and measuring their growth kinetics in leucodepleted and non-leucodepleted platelet concentrates

To evaluate the BacT/Alert automated blood culture system for the detection of bacteria in platelet concentrates, and to determine bacterial growth kinetics in leucodepleted and non‐leucodepleted units.

Evaluation of a Malaria Antibody ELISA and Its Value in Reducing Potential Wastage of Red Cell Donations from Blood Donors Exposed to Malaria, with a Note on a Case of Transfusion‐Transmitted Malaria

Background and objectives: Blood donations are often wasted for lack of a satisfactory procedure to evaluate donors potentially exposed to malaria. Materials and methods: We evaluated a commercial ELISA for the detection of antibodies to malaria and compared it with an immunofluorescent antibody test (IFAT). Results: When 5,311 sera from routine non‐exposed donors were tested, 24 (0.45%) were positive by the ELISA, using a Plasmodium falciparum antigen. Seventeen were subjected to confirmatory testing but none were positive by IFAT. Of 1,000 donors potentially exposed in endemic areas 15 (1.5%) were repeatably reactive by ELISA. 10 of these were tested by IFAT and 2 were positive. When 150 patients attending the Hospital for Tropical Diseases in London with acute malaria were tested, 73% of those infected with P. falciparum were repeatably reactive for malarial antibodies by ELISA and 56% with Plasmodium vivax. Of 88 stored clinical sera tested by both IFAT and ELISA 56 were positive by IFAT and of these 52 (93°/0) were positive by ELISA. Conclusion: The ELISA is sufficiently sensitive and specific to screen at‐risk donors. Its use could safely retrieve 40,000 red cell units currently discarded each year in Great Britain.

HBV DNA levels and transmission of hepatitis B by health care workers

BACKGROUND Laboratory-based study funded by the Research and Development Division of the Department of Health to inform the decision making on guidelines for the conduct of exposure prone procedures (EPPs) by health care workers who are hepatitis B carriers. OBJECTIVES Define the quantity and nature of hepatitis B virus (HBV) DNA in hepatitis carriers whose serum does not contain hepatitis B e antigen (HBeAg) and in surgeons previously cleared to conduct EPPs who have transmitted HBV to their patients. STUDY DESIGN Cross-sectional survey using HBV DNA quantification, genotyping and sequencing comparing transmitting surgeons and asymptomatic carriers. RESULTS HBV DNA could be detected and quantified in 64.5% (136 of 211) of carriers whose serum did not contain HBeAg with a median level 3.6 log(10) copies/ml (range of 5.7 log(10) copies). Pre-core mutation appeared not to affect the HBV DNA level, however, all surgeons carried codon 28 variants and transmitted these variants to their patients. The lowest HBV DNA level in a transmitting surgeon was 4 x 10(4) copies/ml. CONCLUSIONS Pre-core mutations are common in carriers whose serum does not contain HBeAg and do not specifically identify carriers whose HBV DNA levels are high. It was possible to define a level of virus above which transmission of hepatitis B during conduct of EPPs could not be excluded.