Congresos y reuniones científicas
Título:
Performance of a commercial assay for the diagnosis of Influenza A (H1N1) infection in comparison to the Centers for Disease Control and Prevention´s (CDC) real-time RT-PCR Protocol
Autor/es:
GALLEGO, SANDRA; CASTRO, GONZALO MANUEL; BARBÁS, MARIA GABRIELA; BAUMEISTER, ELSA; KADEMIAN, SILVIA; DE LEÓN, JUAN; CUDOLA, ANALIA
Lugar:
Ciudad Autónoma de Buenos AIres
Reunión:
Congreso; III International Clinical Virology Symposium and Advances in Vaccines; 2010
Institución organizadora:
Pan American Society for Clinical Virology
Resumen:
Introduction: At the time of Influenza A (H1N1) emergency, the WHO responded with remarkable speed releasing guidelines and a protocol for a real-time RT-PCR (rRT-PCR) assay. Moreover, in Argentina, a rRT-PCR kit from ROCHE for H1N1 detection was available. The aim of the study was evaluate the performance of the kit ?Real Time ready Influenza A/H1N1 Detection Set? (June 2009 version)-ROCHE in comparison to the CDC?s reference rRT-PCR protocol.
Materials and Methods: At the Central Laboratory of Cordoba, 1341 nasal and/or pharyngeal swabs were studied for Influenza A H1N1 by rRT-PCR, using the CDC protocol. CDC criteria were adopted to consider a sample as positive or negative. Of 1341 samples, 136 (10%) were tested by both, the CDC protocol and the H1N1 rRT-PCR kit - ROCHE, strictly under manufacturer?s instructions.
Statistical Analysis of data was performed by means of EPIDAT 2.0 software.
Results: Of 136 studied samples, 72 were positive for influenza A (H1N1), 34 negative and 30 positive for Influenza A, by CDC?s rRT-PCR protocol. Results of these samples by the rRT-PCR kit - ROCHE are shown bellow:
Assay Genes
detection Influenza A (H1N1) Influenza A Negative
Roche + A+/H1+
A+/H1- 52
8 6
10 2
Roche ? A-/H1- 12 14 32
Total 72 30 34
Discordant results were found: 8 samples classified as H1N1 by the CDC protocol, resulted positive only for InfA gene by Roche; and 6 samples that were positive for InfA gene by the CDC protocol, resulted positive for InfA and H1 genes by Roche.
Global sensitivity of Roche assay for detection of InfA gene in presence or absence of H1 gene was 74.5% (76/102). The sensitivity for detecting samples that were only positive for InfA gene (absence of H1 gene) was 33.33% (10/30) whereas, the sensitivity for samples positives for H1N1 (presence of InfA gene and any other swine gene) was 72.2% (52/72). The specificity of the assay was 94.1% (32/34).
Conclusions: Roche?s assay failed to detect 20 samples from patients infected with the novel pandemic strain and 14 samples from individuals infected with Influenza A. This study highlights the importance of evaluating sensitivity and specificity of the new kits as soon as they become available. In sanitary emergencies besides the need for alternative assays available, the quality of them should not be disregarded.