Laboratory evaluation of the BD MAX MRSA assay.

A comparison between the BD MAX MRSA and Xpert MRSA assays was performed using 239 nares samples. A 97.9% overall agreement between the two molecular assays was observed. The BD MAX MRSA assay proved to be a reliable alternative for a highly automated system to detect methicillin-resistant Staphylococcus aureus (MRSA) in patient nares samples.

Performance evaluation of the Aptima CMV quant assay using plasma and non-plasma samples.

BACKGROUND: Cytomegalovirus (CMV) infection has a major negative impact on transplantation and is associated with increased morbidity and mortality in this patient population. Quantitation of CMV infections using a molecular test is the preferred method for monitoring patients post-transplant. For this analysis, we compared the Aptima CMV Quant Assay (Aptima CMV) on the Panther system to the ELITech MGB Alert® CMV 3.0 ASR (MGB CMV) run on the ELITe InGenius®. METHODS: The analytical performance of the assay was assessed using commercially available CMV reference panels that meet the 1st WHO International Standard for Human Cytomegalovirus for nucleic acid amplification techniques. The clinical performance of the assay was determined using 249 plasma and non-plasma samples. RESULTS: The 95% LOD of the Aptima assay was determined to be 50 IU/mL and 200 IU/mL for the MGB CMV assay. A strong linear correlation with the reference panel (R2 = 0.9945), excellent reproducibility, and accuracy (R2 = 0.986) over the detection range of the assay was observed. Of the 249 clinical samples tested, only 17 (6.8%) yielded discordant results which were at or near the lower limit of quantification of the assays. Although the Aptima CMV assay demonstrated excellent concordance of qualitative results to the MGB CMV assay for all samples, the MGB CMV quantified CMV DNA at an average of 0.5 Log IU/mL higher than Aptima CMV. CONCLUSION: The Aptima CMV assay is both sensitive and accurate in quantifying CMV in both plasma and non-plasma specimens on the fully automated Panther system.

Validation of a modified CDC assay and performance comparison with the NeuMoDx™ and DiaSorin® automated assays for rapid detection of SARS-CoV-2 in respiratory specimens.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has spread rapidly around the globe since it was first identified in December of 2019 in Wuhan, China. In a race to contain the infection, researchers and healthcare officials have developed several assays to help diagnose individuals with COVID-19. To help laboratories decide what assay to bring into testing lines, factors such as assay availability, cost, throughput, and TAT should be considered. Here we validated a modified version of the CDC assay and used it as a reference to evaluate the performance of the NeuMoDxTM SARS-CoV-2 and DiaSorin SimplexaTM Covid-19 Direct assays. In silico analysis and clinical sample testing showed that the primers/probes designed by the CDC were specific to the SARS-CoV-2 as they accurately detected all reactive samples with an assay LoD of 200 copies/mL. The performance of the three assays were analyzed using 159 nasopharyngeal swabs specimen tested within 1-5 days after routine testing. A 100 % agreement was observed between the commercial assays and the modified CDC SARS-CoV-2 assay. A deeper look at the Ct values showed no significant difference between NeuMoDx and the modified CDC SARS-CoV-2 assay, whereas DiaSorin had lower overall Ct values than the modified CDC SARS-CoV-2 assay. NeuMoDx and DiaSorin workflows were much easier to perform. NeuMoDx has the highest throughput and shortest TAT, whereas although the modified CDC SARS-CoV-2 assay has comparable throughput to DiaSorin, it has the longest hands-on time and highest TAT.