Xpert Flu for point-of-care diagnosis of human influenza in industrialized countries

Abstract

Respiratory infections, particularly those caused by influenza viruses, represent the third-most important cause of death in the world due to infectious diseases. Nevertheless, despite the enormous publicity attracted by epidemics due to these viruses, laboratory diagnosis, documentation and recording of respiratory diseases is still unsatisfactory. Available diagnostic tests capable of providing results rapidly are either limited and insufficiently sensitive or highly sensitive and specific but insufficiently rapid. Considerable investment and research efforts have been made towards the development of new diagnostics for influenza A and B viruses and the Xpert^® Flu assay (Cepheid^®, CA, USA) has emerged as one of the most promising. In this article, we review current knowledge of the Xpert Flu test, discuss its potential value as a point-of-care test and outline the potential leads for future development.

Keywords::

• diagnosis
• influenza A
• influenza B
• molecular diagnostics
• PCR
• point-of-care
• respiratory infection

Financial & competing interests disclosure

RN Charrel has received financial support from Cepheid for traveling and accommodation in scientific meetings. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Respiratory infections constitute the third highest cause of death in the world.

• Influenza virus infection is the leading cause of death due to lower respiratory tract infections.

• Rapid laboratory detection of influenza virus is pivotal in the monitoring of patients in health structures.

• The major drawback of rapid influenza antigen-based detection tests is the poor sensitivity that demand second-line testing for the rapid influenza antigen detection tests-negative samples.

• The Xpert Flu assay is a properly evaluated molecular test for detection and identification of the principal human influenza viruses that is amenable for point-of-care settings with excellent sensitivity (FluA [92.7–100%], FluB [94.8%]) and specificity (FluA [98.6–100%], FluB [100%]) observed with the recent versions.

• The performance of the Xpert Flu assay has been evaluated in several peer-reviewed articles.

• Future access to multiplex tests will facilitate increased coverage of respiratory infections using a syndromic approach.