Characteristics of participating laboratories over time

From 16 (in the RTCIT trial of 2009) to 50 national laboratories (in the FAT trial of 2016) participated annually in the proficiency test. Globally, over the 10 years of the study period, 73 different laboratories participated, of which 59% were from Europe (including 38% from the European Union (EU)), 17% from Africa, 12% from Asia, 11% from the Americas and 1% from Oceania. Considering the regular and repeated participation from one year to another, the representativity of participants over the five continents was 55% from the EU, 18% from the non-EU part of Europe, 13% from Africa, 7% from the Americas, 5% from Asia and 2% from Oceania. The evolution in participants per continent over the years is shown in Table 1. More than 70% of the total number of laboratories participating yearly in the proficiency testing (PT) were from Europe. Because participation in diagnosis proficiency tests organised by the EURL is mandatory, regulatory and free of charge for NRLs within the EU, many study participants are from the EU (Commission regulations No. 737/2008 and No. 415/2013 [13]).