Evaluation of Inconclusive Results on the Cepheid X-Pert Xpress Platform (GXP) for the Diagnosis of Severe Acute Respiratory Syndrome-2: A Narrative Literature Review

Abstract

Introduction:Molecular assay for diagnosing and detecting SARS-COV-2 is an essential tool in pandemic management, allowing for early informed decision-making. Worldwide, the gold standard for testing SARS-COV-2 includes real-time reverse transcription-polymerase chain reaction assay (RT-PCR). The Cepheid Xpert-Xpress was authorized for emergency diagnosis of SARS-COV-2. This platform demonstrated various advantages, including faster results, due to a decreased turnaround time, and decreased contamination risk. However, inconclusive results often leave clinicians uncertain regarding individual patient management decisions. Often leading to more confusion than answers.The aim of this literature review includes the following: identify the frequency and clinical implications of inconclusive results for SARS-COV-2 diagnosis utilizing GeneXpert assaywhether inconclusive results should be interpreted as negativeassessing the reliability of the GeneXpert platform to diagnose SARS-COV-2Method:A narrative literature review was conducted with eight critically appraised articles which met the inclusion criteria.After the initial data collection, the SANRA Framework was implemented to aid in the sorting and filtering of data. The analysis of data was conducted with a critical appraisal tool.Results:The GeneXpert SARS-COV-2 assay demonstrated high sensitivity and specificity. Studies indicated that inconclusive results associated with a high cycle-threshold value (CT-value) of more than thirty-five on the Cepheid Xpert Xpress were associated with a decreased viral load and, thus, decreased infectivity. However, numerous factors influence the CT-value, such as specimen integrity. Thus, results must not be interpreted in isolation.Conclusion:This narrative literature review demonstrated the need for institutions to assist clinicians with decision-making regarding inconclusive results. A flow diagram grading a patient’s risk of having SARS-COV-2 with an inconclusive result could be of immense value. The flow diagram should incorporate the current epidemiology in the area, patient symptomology and risk and duration of exposure.