Results of Proficiency Testing for Trichinella in Poland, 2015-2019

Trichinella proficiency testing in Southeastern European countries

In some Southeastern European (SEE) countries, like Serbia, Romania, and Bulgaria, trichinellosis is one of the most important foodborne zoonotic diseases. In those countries, EU regulation and local authorities require the staff of laboratories performing official controls on meat to be properly trained and to check their competence by participating regularly in proficiency testing (PT). PTs are organized by National Reference Laboratories for Trichinella of each country and involve all official laboratories testing meat. In Romania and Bulgaria, the organization of PT for the detection of Trichinella larvae in meat by Magnetic Stirrer Method (MSM) started in 2012. In Croatia and Serbia PT was first organized in 2015 and 2017, respectively. This study presents data on the performance obtained by official laboratories of SEE countries that organize PT at national level and compares the performance obtained by laboratories belonging to different countries. Results suggest that the constant participation in PT leads to an increase in the performance of participating laboratories by positively affecting the staff accuracy in sample testing by MSM. Since the percentage of recovered larvae was in some cases suboptimal (<80%) and occasionally very poor (<40%), there is room for improvement. The regular participation in PT by laboratories involved in official controls on meat intended for human consumption is fundamental to guarantee consumer safety.

Evaluation of factors contributing to variability of qualitative and quantitative proficiency testing for SARS-CoV-2 nucleic acid detection

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to unprecedented social and economic disruption. Many nucleic acid testing (NAT) laboratories in China have been established to control the epidemic better. This proficiency testing (PT) aims to evaluate the participants' performance in qualitative and quantitative SARS-CoV-2 NAT and to explore the factors that contribute to differences in detection capabilities. Two different concentrations of RNA samples (A, B) were used for quantitative PT. Pseudovirus samples D, E (different concentrations) and negative sample (F) were used for qualitative PT. 50 data sets were reported for qualitative PT, of which 74.00% were entirely correct for all samples. Forty-two laboratories participated in the quantitative PT. 37 submitted all gene results, of which only 56.76% were satisfactory. For qualitative detection, it is suggested that laboratories should strengthen personnel training, select qualified detection kits, and reduce cross-contamination to improve detection accuracy. For quantitative detection, the results of the reverse transcription digital PCR (RT-dPCR) method were more comparable and reliable than those of reverse transcription quantitative PCR (RT-qPCR). The copy number concentration of ORF1ab and N in samples A and B scattered in 85, 223, 50, and 106 folds, respectively. The differences in the quantitative result of RT-qPCR was mainly caused by the non-standard use of reference materials and the lack of personnel operating skills. Comparing the satisfaction of participants participating in both quantitative and qualitative proficiency testing, 95.65% of the laboratories with satisfactory quantitative results also judged the qualitative results correctly, while 85.71% of the laboratories with unsatisfactory quantitative results were also unsatisfied with their qualitative judgments. Therefore, the quantitative ability is the basis of qualitative judgment. Overall, participants from hospitals reported more satisfactory results than those from enterprises and universities. Therefore, surveillance, daily qualitiy control and standardized operating procedures should be strengthened to improve the capability of SARS-CoV-2 NAT.

Validation of the Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples Based on Proficiency Tests Result

Trichinellosis is a zoonotic disease caused by the nematodes of the genus Trichinella. Infection takes place through the consumption of infected meat containing live larvae. The only way to prevent the disease is to break its epizootic chain. To ensure effective control of Trichinella spp., a range of preventive and control measures have been undertaken. These efforts have been focused on controlling Trichinella in domestic pigs, the main source of the disease. Artificial digestion is also the reference point for other methods for Trichinella risk control. Descriptive data validation of the digestion assay was presented in 1998 based on results published by scientific laboratories. Herein, we supplement those data by characterizing the method’s performance in inter-laboratory comparisons. The source of data was the results of Proficiency Testing conducted in 2015–2019. Samples were contaminated by 0, 1, 3, and 5 larvae. In total, 7580 samples were examined by the laboratories. Based on Proficiency Testing results, the main parameters characterizing the method performance in field conditions were established as follows: specificity, 97.3%; sensitivity, 86.5%; accuracy, 89.2%; uncertainty, 0.3; limit of detection (LOD), 1 larva; and limit of quantification (LOQ), 3 larvae.