Nationwide external quality assessment of SARS-CoV-2 nucleic acid amplification tests in Japan

Objectives

We conducted a nationwide external quality assessment (EQA) study of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid amplification testing in Japan.

Methods

A total of 563 public health and private sector laboratories participated. The EQA samples comprised 6 RNA and full-process controls.

Results

The overall agreements were 99.3% and 97.9% for the RNA and full-process controls, respectively. A total of 530/563 (94.1%) laboratories reported correct results; public health laboratories had the highest accuracy. Thirty-three laboratories reported at least one incorrect result (26 laboratories of medical facilities, 5 commercial laboratories, 1 public health laboratory, and 1 other). Sixteen laboratories of medical facilities that used a fully automated assay system failed to detect the presence of the full-process control, due to inherent insufficiency in the limit of detection (LOD). Other causes of incorrect results included failure to ensure the LOD (n = 13), error in result judging or reporting (n = 3), and error in sample handling (n = 1).

Conclusions

Performance was mostly dependent on the laboratory category and assay evaluation, particularly the LOD. Guidance should be developed based on these results, particularly in the phase of new entry into laboratory services for SARS-CoV-2.

Evaluation of the basic assay performance of the GeneSoc® rapid PCR testing system for detection of severe acute respiratory syndrome coronavirus 2

In the ongoing coronavirus disease 2019 (COVID-19) pandemic, PCR has been widely used for screening patients displaying relevant symptoms. The rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enables prompt diagnosis and the implementation of proper precautionary and isolation measures for the patient. In the present study, we aimed to evaluate the basic assay performance of an innovative PCR system, GeneSoC^® (Kyorin Pharmaceutical Co. Ltd., Tokyo, Japan). A total of 1,445 clinical samples were submitted to the clinical laboratory, including confirmed or suspected cases of COVID-19, from February 13 to August 31. Specimen types included nasopharyngeal swabs. The sampling was performed several times for each patient every 2–7 days. Using this system, sequences specific for SARS-CoV-2 RNA could be detected in a sample within 10–15 min using the microfluidic thermal cycling technology. Analytical sensitivity studies showed that GeneSoC^® could detect the target sequence of the viral envelope and RNA-dependent RNA-polymerase (RdRp) genes at 5 and 10 copies/μL, respectively. The precision of the GeneSoC^® measurements using clinical isolates of the virus at a concentration of 10³ copies/μL was favorable for both the genes; within-run repeatability and between-run reproducibility coefficient of variation values were less than 3% and 2%, respectively; and the reproducibility of inter-detection units was less than 5%. Method comparison by LightCycler^® 480 showed the positive and negative agreement to be 100% [(174/174) and (1271/1271), respectively]. GeneSoC^® proved to be a rapid and reliable detection system for the prompt diagnosis of symptomatic COVID-19 patients and could help reduce the spread of infections and facilitate more rapid treatment of infected patients.