Multicenter study evaluating novel multi-specimen pooling assay for the detection of SARS-CoV-2: High sensitivity and high throughput testing

Performance evaluation of the cobas SARS-CoV-2 Duo, a novel qualitative and quantitative assay, for the detection of SARS-CoV-2 RNA

IMPORTANCE

Quantitative SARS-CoV-2 tests for viral load are necessary to guide patient treatment, as well as to determine infection control measures and policies. Although the real-time RT-PCR assays can report the Ct value to estimate the viral load, there are several serious concerns regarding the use of Ct values. Importantly, Ct values can vary significantly among between- and within-run methods. The diagnostic performance of the cobas SARS-CoV-2 Duo is appropriate. It is a precise, accurate, and sensitive method for the detection of SARS-CoV-2 RNA and is comparable to two qualitative assays (the cobas SARS-CoV-2 and the Liat cobas SARS-CoV-2 and Inf A/B). In contrast, using the Ct value to estimate viral load is not reliable, and utilization of a quantitative detection test, such as the cobas SARS-CoV-2 Duo, to accurately measure the viral load is needed.

Setting up a three‐stage pre‐endoscopy triage during the coronavirus disease 2019 pandemic: A multicenter observational study

Objectives

Between May and July 2021, the coronavirus disease 2019 (COVID‐19) pandemic led to a sharp surge in community transmission in Taiwan. We present a three‐stage restructuring process of pre‐endoscopy triage at the beginning of the pandemic, which can support urgent endoscopic procedures while protecting endoscopy staff.

Methods

The pre‐endoscopy triage framework was set up with three checkpoints at the hospital entrance, outpatient department, and endoscopy unit, with a specific target patient population and screening methods. Relevant data included the number of endoscopic procedures performed, outpatient department visits, and performing screening methods such as temperature measurement, travel, occupation, contact, and clustering history checking, polymerase chain reaction assay, and rapid antigen test.

Results

Forehead temperature measurement and verification of travel, occupation, contact, and clustering history provided rapid, easy, and early mass screening of symptomatic patients at the hospital entrance. During the pandemic, outpatient department visits and endoscopic procedures decreased by 37% and 64%, respectively. The pre‐endoscopy screening methods used displayed regional variations in COVID‐19 prevalence. Among 16 endoscopy units with a community prevalence of ≥ 31.04 cases per 100,000 residents, 12 (75%) used polymerase chain reaction assay and four (25%) used rapid antigen test to identify asymptomatic patients before endoscopy. Of 6540 pre‐endoscopy screening patients, 15 (0.23%) tested positive by laboratory testing. No endoscopy‐related nosocomial COVID‐19 infections were reported during the pandemic.

Conclusions

We present a three‐stage pre‐endoscopy triage based on the local laboratory capacity, medical resources, and community prevalence. These measures could be useful during the COVID‐19 pandemic.

High-Throughput and Automated Detection of HLA-B*27 Using the LabTurboTM AIO System

The adoption of an automated system can decrease the hands-on time requirements in a clinical laboratory setting. For the detection of HLA-B*27, implementing a high-throughput and fully automated system has several advantages over using manual methods. Therefore, this study aimed to evaluate automation efficiency for the detection of HLA-B*27. Peripheral blood samples were obtained from 50 participants, and DNA was isolated from these samples. A Pharmigene PG27 detection kit was used for the qualitative detection of HLA-B*27. The performances of the semi-automated and fully automated LabTurbo^TM AIO systems in the detection of HLA-B*27 were compared. The mean absorbance (optical density) values for the Maelstrom^TM 8 and LabTurbo^TM AIO systems were found to be 1.88 and 1.9, respectively. The housekeeping gene was amplified and quantified using a real-time PCR assay across all DNA extracts to check the quality of the extracted human DNA. The results were expressed as the cycle threshold (Ct) values for all DNA extracts from both platforms. The mean Ct values for the Roche Cobas z480 and LabTurbo^TM AIO systems were found to be 22.7 and 20.4, respectively. This study demonstrated that the semi-automated method and the LabTurbo^TM AIO system yield consistent results for the detection of HLA-B*27. However, compared to the semi-automated method, the LabTurbo^TM AIO system provides standardized procedures, avoids manual handling, and improves turnaround time.

Using Real-Time PCR Fluorescence Reaction Values to Improve SARS-CoV-2 Virus Detection and Benefit Clinical Decision-Making

This study aimed to compare the SARS-CoV-2 nucleic acid detection results of the BD MAX™ System and other platforms to formulate an optimized laboratory verification process. The re-examination of 400 samples determined as positive by BD MAX™ indicated that the inconsistency rate between BD MAX™ and the other platforms was 65.8%; the inconsistency rate of single-gene-positive results was as high as 99.2%. A receiver operating characteristic curve was drawn for the relative light unit (RLU) values of samples positive for a single gene, and RLU 800 was used as the cutoff. After setting the retest standard as single-gene positive and RLU ≥ 800, the number of the 260 BD MAX™ single-gene positives that needed to be confirmed again was 36 (13.8%) and the number that could be directly reported as negative was 224 (86.2%). This verification process can shorten the reporting period and speed up the epidemic adjustment time and turnover rate of special wards, thereby improving SARS-CoV-2 detection efficiency and clinical decision-making.