RESUMEN
BACKGROUND AND OBJECTIVES: Since 2004, bacterial screening of platelets has been required in the USA and is also done on a voluntary basis in many European countries. The German Red Cross blood donor services conducted a prospective multicentre study in order to investigate the prevalence of bacterially contaminated pool platelet concentrates and apheresis platelet concentrates. This substudy compares three different bacterial detection systems. STUDY DESIGN AND METHODS: Platelet concentrates were tested in parallel with BacT/ALERT, Scansystem and Pall eBDS (n = 6307) in pool platelets. Apheresis platelets were tested in parallel with BacT/ALERT and Pall eBDS (n = 4730). All initially positive results were evaluated by a standardized procedure including evaluation by a microbiology reference laboratory. RESULTS: One in 6307 pool platelets were confirmed positive by BacT/ALERT, whereas Pall eBDS and Scansystem failed to detect these samples. Only three samples were initially reactive with Pall eBDS without proof of any bacteria strains. The rate of false-positive results was substantially higher for BacT/ALERT (0.25%, 28 in 11,037 tested samples) than for eBDS (0.03%, 3 in 11 037 tested samples) or Scansystem (0.0%, 0 in 6307 tested samples). Three of 4730 apheresis platelets were confirmed positive by BacT/ALERT. These were negative with Pall eBDS. CONCLUSION: Sensitivity was best for BacT/ALERT, whereas specificity was enhanced for Pall eBDS and Scansystem. Scansystem required specially trained staff, whereas BacT/ALERT and Pall eBDS were easy, quick, user-friendly and objective methods.
Asunto(s)
Bacterias/aislamiento & purificación , Técnicas Bacteriológicas/instrumentación , Donantes de Sangre , Plaquetas/microbiología , Transfusión de Plaquetas , Infecciones Bacterianas/prevención & control , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Sensibilidad y EspecificidadRESUMEN
The aim of the study was to evaluate a new ELISA for detection of HIV-1, HIV-2 and HIV-1 subtype 0 (HIV-0) antibodies. The assay format is based on the antigen sandwich principle. To enable specific detection of HIV-0 antibodies, in addition to HIV-1 and HIV-2 antigens HIV-0 antigen is used for coating the solid phase and for the conjugate. The results show that all 12 HIV-0 samples tested were detected with a high degree of reactivity, as were all the 1,144 anti-HIV-1 and 424 anti-HIV-2 positive samples. The capacity of the test to enable early detection of seroconversions is equivalent to that of other sandwich ELISAs. The specificity of the assay was determined to be 99.89/99.94% (initial/after retest) using 58,366 samples, which is superior to the other ELISAs used for comparison. Even with difficult samples (i.e. samples of African origin, samples known to cause false-positive reactivity in different ELISAs, or samples containing potential interference factors) there were very few false-positive reactions. Therefore, the new assay is well suited for screening blood donations as well as for evaluating samples from patients of different geographic origin.
Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Anticuerpos Anti-VIH/sangre , Seropositividad para VIH/diagnóstico , VIH-1/inmunología , VIH-2/inmunología , Estudios de Evaluación como Asunto , Humanos , Valor Predictivo de las Pruebas , Juego de Reactivos para Diagnóstico , Sensibilidad y EspecificidadRESUMEN
Standard practice of platelet storage at room temperature may contribute to the risk of sepsis after platelet transfusion. Platelets in vitro inoculated with 10(3) or more different microorganisms showed logarithmic bacterial growth throughout the 5 days of storage. These data support the hypothesis that bacterial contamination of platelets might become clinically significant during the 5 days of storage.
Asunto(s)
Infecciones Bacterianas/transmisión , Conservación de la Sangre , Transfusión Sanguínea , Recuento de Colonia Microbiana , Transfusión de Plaquetas , Infecciones Bacterianas/microbiología , Plaquetas/microbiología , Humanos , Factores de RiesgoRESUMEN
With a new method which is easy to handle, leukocyte depleted neocyte enrichment can be obtained from ordinary whole blood units using centrifugation. In comparison to alternative methods less time for preparation will be needed without significant changes in enzyme activities during storage indicating red cell lesion.