Evaluation of the Cepheid Xpert Flu Assay for Rapid Identification and Differentiation of Influenza A, Influenza A 2009 H1N1, and Influenza B Viruses

Novak-Weekley, Susan; Marlowe, Elizabeth M.; Poulter, Melinda D.; Dwyer, Dominic E.; Speers, David; Rawlinson, William D.; Baleriola, Cristina; Robinson, Christine C.

doi:10.1128/jcm.06520-11

Cited by 70 publications

(63 citation statements)

References 25 publications

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“…This is the first time that the Xpert Flu rapid diagnostic test has been evaluated in a high-acuity ED population, where undifferentiated patients are evaluated and treated. In this high-acuity target population, Xpert Flu had high overall sensitivity and specificity compared those of ProFluϩ, similar to what has been reported by several previous studies performed in more general patient populations (4,(8)(9)(10)(11)(12)(13). From a clinical viewpoint, diagnosing influenza and initiating antiviral treatment in the admitted population is most critical, as antivirals have shown substantial benefit, including a reduction in mortality rates, in this population (14-16).…”

supporting

confidence: 84%

Evaluation of the Xpert Flu Rapid PCR Assay in High-Risk Emergency Department Patients

et al. 2014

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We prospectively evaluated the performance of Cepheid's GeneXpert Xpert Flu assay in a target population of 281 adults presenting to the emergency department with an acute respiratory illness who met Centers for Disease Control and Prevention (CDC) criteria for recommended antiviral treatment. Compared with the Prodesse ProFlu؉ assay, Xpert Flu had an overall sensitivity of 95.3% and specificity of 99.2%. The majority of patients seeking care for influenza and other respiratory viruses present to episodic outpatient care settings, such as emergency departments (EDs) or other urgent or primary care settings, where rapid diagnosis and treatment are critical (1). Due to nonspecific symptoms, a provider's clinical diagnosis of influenza has low sensitivity, leading providers to rely on diagnostic testing for an accurate influenza diagnosis (2). Most commercially available real-time PCR (rt-PCR) tests are typically run in batches and require separate nucleic acid extraction, which significantly delays the results. The current antigen detection tests are rapid but have poor-to-moderate sensitivities, ranging from 10% to 70% (3). Rapid random-access PCR-based influenza tests, such as the GeneXpert Xpert Flu assay (Cepheid, Sunnyvale, CA, USA), may have clinical utility in filling this diagnostic gap, since it has a reported time to result of approximately 80 min and has a significantly higher sensitivity than rapid antigen detection tests (4).Prior to integration into routine clinical use, the clinical performance of Xpert Flu in the target population requires evaluation. Although clinicians in the outpatient episodic care setting may test an array of patients, accurate and rapid influenza testing with Xpert Flu would be most important in patients for whom the test result would impact clinical management, namely, those who meet the Centers for Disease Control and Prevention (CDC) criteria for antiviral therapy and are at risk for potential influenza-related complications. Several of these conditions, such as advanced age and pneumonia, have been associated with the decreased sensitivity of rapid antigen-based testing, highlighting the importance of evaluating Xpert Flu in this population (5). In order to fully translate rapid PCR-based testing into clinical practice, we prospectively evaluated the sensitivity and specificity of Xpert Flu in adult ED patients with an acute undifferentiated respiratory illness who met CDC criteria for recommended antiviral treatment.Adult ED patients with an undifferentiated acute respiratory illness who met CDC criteria for recommended influenza antiviral treatment at an urban university-affiliated tertiary-care ED were prospectively enrolled between December 2012 and March 2013. After written consent was obtained, as approved by the Johns Hopkins University institutional review board (IRB), a nasopharyngeal swab was collected from each patient and placed in 3 ml of viral transport medium (MicroTest M4RT; Remel, Lenexa, KS, USA). All the samples were aliquoted, stored at Ϫ70°C until com...

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supporting

confidence: 84%

Evaluation of the Xpert Flu Rapid PCR Assay in High-Risk Emergency Department Patients

et al. 2014

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“…In our previous study (1), the Xpert Flu test exhibited respective sensitivity (Se) and specificity (Sp) values of 100% and 100% for the detection of influenza A virus (Flu A), 98.4% and 100% for the detection of H1N1-2009, and 80.77% and 100% for the detection of Flu B. A low sensitivity (76.5%) for Flu B detection was also reported by Li et al (2), whereas other studies reported sensitivity and specificity values ranging from 87.5% to 100% and from 99.2% to 100%, respectively (3)(4)(5)(6) (1), we compared the results observed with the Xpert Flu assay with those of the real-time RT-PCR assay routinely used (Table 1) (7). As recommended by the manufacturer, 300 l of the 1-ml swab's medium was loaded into an Xpert cartridge and processed on a 4-module GeneXpert system.…”

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confidence: 81%

Improved Sensitivity of the Novel Xpert Flu Test for Detection of Influenza B Virus

Salez¹,

Lamballerie²,

Zandotti³

et al. 2013

J Clin Microbiol

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Fully automated easy-to-use integrated molecular systems have demonstrated their capability for rapid documentation of respiratory specimens, especially in point-of-care (POC) laboratories. In our previous study (1) (1), we compared the results observed with the Xpert Flu assay with those of the real-time RT-PCR assay routinely used (Table 1) (7). As recommended by the manufacturer, 300 l of the 1-ml swab's medium was loaded into an Xpert cartridge and processed on a 4-module GeneXpert system. The specimens corresponding to discrepant results were extracted again for total nucleic acid using EZ1 Virus Minikit v2.0 and an EZ1 Advanced XL Biorobot (Qiagen, Courtaboeuf, France).In the group of 77 RT-PCR ϩ samples, the five age categories (Ͻ1 year, 1 to 4 years, 5 to 14 years, 15 to 49 years, and Ͼ50 years) were distributed in terms of numbers of patients (and sex ratios) as 11 (2.67), 22 (1.75), 10 (0.67), 12 (0.50), and 22 (1.75), respectively. A total of 73 of the 77 RT-PCR ϩ samples were found positive using the Xpert FluB test. The 4 samples that provided discrepant results were confirmed by retesting using the RT-PCR to assess that the freeze/thaw steps did not result in a drop of the viral load to an undetectable level. The remaining 13 samples were negative with the two assays. No "indeterminate" result was noticed in this study performed with the Xpert Flu assay. The Xpert FluB test exhibited 94.81% sensitivity and 100% specificity for the detection of Flu B, although the selection of samples was purposely made without the intention to address specificity, which proved satisfactory with the previous version of the Xpert Flu assay (1). From these results, it appears that the new version of the test has improved sensitivity for the detection of Flu B. ϩ /Xpert FluB Ϫ samples (P Ͻ 0.05). The samples with low viral loads were more likely to provide a false-negative result with the Flu B Xpert test. In conclusion, the sensitivity of the novel Xpert FluB test has greatly improved in reference to the previous version (1). ACKNOWLEDGMENTS

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“…Unlike other viruses, rapid and accurate diagnosis of influenza is necessary for prompt administration of antiviral therapy, mainly oseltamivir, which should be administered within 48 h of symptom onset (8). Additional benefits of rapid identification are infection control, public health notification and tracking, and prevention of unnecessary use of antibiotics, hospital procedures, and laboratory tests (9)(10)(11).…”

mentioning

confidence: 99%

Evaluation of Alere i Influenza A&B for Rapid Detection of Influenza Viruses A and B

Roth²,

et al. 2014

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Evaluation of the Cepheid Xpert Flu Assay for Rapid Identification and Differentiation of Influenza A, Influenza A 2009 H1N1, and Influenza B Viruses

Cited by 70 publications

References 25 publications

Evaluation of the Xpert Flu Rapid PCR Assay in High-Risk Emergency Department Patients

Evaluation of the Xpert Flu Rapid PCR Assay in High-Risk Emergency Department Patients

Improved Sensitivity of the Novel Xpert Flu Test for Detection of Influenza B Virus

Evaluation of Alere i Influenza A&B for Rapid Detection of Influenza Viruses A and B

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