The 2023 National Proficiency Test for molecular detection of shrimp infectious myonecrosis virus (IMNV) in China

Abstract

Infectious myonecrosis virus (IMNV), an emerging virus that can cause severe viral disease in penaeid shrimp, was first confirmed to have spread to China in 2020. In order to standardize diagnostic procedures and reliable detection capability, and to evaluate the performances of aquatic clinical diagnostic laboratories, the executive agency has launched a proficiency test (PT) scheme for the molecular detection of IMNV in China from the year of 2023. In the ring test of IMNV-PT 2023, five tissue samples containing different concentrations of IMNV were provided as a panel of test samples. A total of 68 laboratories participated in the PT test of qualitative and quantitative analysis of the five samples using standard molecular assays. The results showed that 92.65 % (63/68) of the participants correctly reported all samples in the panel using Real-time reverse transcription PCR and 62 participants achieved satisfactory results, one participant using conventional PCR and four participants had not completed the test. Out of the 62 participants in the z-scores analysis, 88.71 % (55/62) achieved acceptable ZB-scores, with two outlier laboratories and five laboratories being questionable. Additionally, 98.39 % (61/62) achieved ZW-scores, with only one laboratory being questionable. Furthermore, the national PT conducted in the present study proved to be an effective tool for evaluating laboratory performance in IMNV molecular testing. This assessment can aid in improving the capabilities of IMNV molecular testing of the participating laboratories, and also provide technical support to enhance the national response to IMN outbreaks.