Timely diagnosis of respiratory tract infections: evaluation of the performance of the Respifinder assay compared to the xTAG respiratory viral panel assay.

BACKGROUND: Respiratory tract infections are the most common cause of hospitalization in infants and young children and are typically caused by viral or, less commonly, bacterial pathogens. Existing non-molecular diagnostic methods have several drawbacks such as limited sensitivity, long turn-a-round time and limited number of pathogens that can be detected. OBJECTIVES: Nucleic acid amplification methods can increase sensitivity and enable the initiation of appropriate interventions without delay. Broad-spectrum detection and identification circumvent the use of individual diagnostic DNA or RNA based assays. At present, several commercial assays are available for broad-spectrum detection. STUDY DESIGN: We compared the performance of the xTAG Respiratory Viral Panel (RVP) (Luminex Molecular Diagnostics, Toronto, Canada) with that of the Respifinder (Pathofinder, Maastricht, Netherlands) for 9 external quality assurance (EQA) panels (QCMD, Scotland) consisting of a total of 106 EQA samples. RESULTS: Both the RVP and the Respifinder assay have an excellent specificity. Sensitivity was 33% and 78% for the RVP and the Respifinder assay, respectively. For both assays, sensitivity was low for weak positive samples. DISCUSSION: The results of our study seem to indicate a better sensitivity for the Respifinder. Analysis of patient samples is necessary to evaluate the clinical performance.

Reflections and proposals to assure quality in molecular diagnostics.

Molecular diagnostic testing has become an important tool in clinical laboratories. Accreditation according to the international quality standard ISO15189:2007 for medical laboratories is required for reimbursement of several molecular diagnostic tests in Belgium. Since the ISO15189:2007 standard applies to medical laboratories in general, the particular requirements for quality and competence are mentioned in general terms, not taking into account the specificities of molecular biology testing. Therefore, the working group "MolecularDiagnostics.be" described a consensus interpretation of chapter 5, Technical requirements, of the ISO standard for application in molecular diagnostic laboratories. The manuscript can be used as an instrument to prepare internal and external audits that meet the 15015189:2007 (chapter 5) criteria.