03388nas a2200517   4500000000100000008004100001260003700042653005700079653002400136653003000160653003700190100001200227700001600239700001600255700001300271700001700284700001200301700001600313700001500329700001100344700001400355700001300369700001600382700001100398700001500409700001200424700001500436700001400451700001300465700001100478700001200489700001900501700001700520700001500537700001600552700001500568700002100583700001400604700001500618245020000633856009900833300001300932490000700945520190400952022001402856       2020                            d  bPublic Library of Science (PLoS)10aPublic Health, Environmental and Occupational Health10aInfectious Diseases10aQuality assessment scheme10aNucleic acid amplification tests1 aCools P1 aLieshout LV1 aKoelewijn R1 aAddiss D1 aAjjampur SSR1 aAyana M1 aBradbury RS1 aCantera JL1 aDana D1 aFischer K1 aImtiaz R1 aKabagenyi J1 aLok JB1 aMcCarthy J1 aMejia R1 aMekonnen Z1 aNjenga SM1 aOthman N1 aShao H1 aTraub R1 aVan Esbroeck M1 aVercruysse J1 aVlaminck J1 aWilliams SA1 aVerweij JJ1 avan Hellemond JJ1 aLevecke B1 aPeriago MV00aFirst international external quality assessment scheme of nucleic acid amplification tests for the detection of Schistosoma and soil-transmitted helminths, including Strongyloides: A pilot study  uhttps://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0008231&type=printable  ae00082310 v143 aBackground<br>
Nucleic acid amplification tests (NAATs) are increasingly being used as diagnostic tools for soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and A. ceylanicum), Strongyloides stercoralis and Schistosoma in human stool. Currently, there is a large diversity of NAATs being applied, but an external quality assessment scheme (EQAS) for these diagnostics is lacking. An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. In the current study, we piloted an international EQAS for these helminths (i) to investigate the feasibility of designing and delivering an EQAS; (ii) to assess the diagnostic performance of laboratories; and (iii) to gain insights into the different NAAT protocols used.<br>

<br>Methods and principal findings<br>
A panel of twelve stool samples and eight DNA samples was validated by six expert laboratories for the presence of six helminths (Ascaris, Trichuris, N. americanus, Ancylostoma, Strongyloides and Schistosoma). Subsequently this panel was sent to 15 globally dispersed laboratories. We found a high degree of diversity among the different DNA extraction and NAAT protocols. Although most laboratories performed well, we could clearly identify the laboratories that were poorly performing.<br>

<br>Conclusions/Significance<br>
We showed the technical feasibility of an international EQAS for the NAAT of STHs, Strongyloides and Schistosoma. In addition, we documented that there are clear benefits for participating laboratories, as they can confirm and/or improve the diagnostic performance of their NAATs. Further research should aim to identify factors that explain poor performance of NAATs.  a1935-2735