False positive congenital cytomegalovirus saliva screening results with an FDA-approved assay at two institutions.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is a significant cause of childhood hearing loss and developmental delay. Congenital CMV screening was implemented at two large hospital-affiliated laboratories using the FDA-approved Alethia CMV Assay Test System. In July 2022, an increase in suspected false-positive results was noted, leading to implementation of prospective quality management strategies. METHODS: The Alethia assay was performed per manufacturer-provided instructions on saliva swab specimens. After discovery of possible elevated false-positive rates, all positive results were confirmed by repeat Alethia testing on the same specimen, orthogonal polymerase chain reaction (PCR) on the same specimen, and/or clinical adjudication. Additionally, root cause analyses were conducted to pinpoint the source of false-positive results. RESULTS: At Cleveland Clinic (CCF), 696 saliva specimens were tested after initiation of the prospective quality management strategy, of which 36 (5.2%) were positive for CMV. Five of 36 (13.9%) were confirmed CMV positive by repeat Alethia testing and orthogonal PCR. Vanderbilt Medical Center (VUMC) tested 145 specimens, of which 11 (7.6%) were positive. Two of 11 (18.2%) confirmed as positive by orthogonal PCR or clinical adjudication. The remaining specimens (31 from CCF and 9 from VUMC) were negative for CMV by repeat Alethia and/or orthogonal PCR testing. DISCUSSION: These findings suggest a false positive rate of 4.5-6.2%, higher than the 0.2% reported for this assay in FDA claims. Laboratories using Alethia CMV may consider prospective quality management to evaluate all positive results. False-positive results can lead to unnecessary follow-up care and testing, and decreased confidence in laboratory testing.

Analytical and Workflow Evaluation of the ARIES Sample-to-Result Molecular Assay for Clostridium difficile.

We evaluated the analytical and workflow characteristics of the ARIES Clostridium difficile assay, a recently developed qPCR-based test for toxigenic C. difficile ARIES was compared to the illumigene C. difficile assay, a commonly employed, loop-mediated amplification technique with similar sample-to-result capabilities. Following illumigene analysis, 122 positive and 164 negative stool specimens were banked for subsequent ARIES testing. The analytical agreement between the platforms was high: 93.4% positive agreement (89.0-97.8%) and 97.5% negative agreement (95.2-99.9%). For discordant specimens, amplification/bidirectional sequencing of tcdA/tcdB demonstrated toxigenic C. difficile in 2/4 illumigene(-)ARIES(+) and 2/8 illumigene(+)ARIES(-) specimens. In a time-motion study, the ARIES assay required less hands-on time than illumigene, but with greater total testing time. Overall, these findings support the ARIES C. difficile Assay as a new option for laboratories in their diagnostic repertoire.

A computerized data-capture system for animal biosafety level 4 laboratories.

The restrictive nature of an Animal Biosafety Level 4 (ABSL4) laboratory complicates even simple clinical evaluation including data capture. Typically, clinical data are recorded on paper during procedures, faxed out of the ABSL4, and subsequently manually entered into a computer. This system has many disadvantages including transcriptional errors. Here, we describe the development of a highly customizable, tablet-PC-based computerized data-capture system, allowing reliable collection of observational and clinical data from experimental animals in a restrictive biocontainment setting. A multidisciplinary team with skills in containment laboratory animal science, database design, and software engineering collaborated on the development of this system. The goals were to design an easy-to-use and flexible user interface on a touch-screen tablet PC with user-supportable processes for recovery, full auditing capabilities, and cost effectiveness. The system simplifies data capture, reduces the necessary time in an ABSL4 environment, offers timely reporting and review of data, facilitates statistical analysis, reduces potential of erroneous data entry, improves quality assurance of animal care, and advances the use and refinement of humane endpoints.