When applied to chickens, the cELISA showed decent Se and moderate Sp, whereas in turkeys, it was more sensitive yet less specific. the detection of AI antibodies without assuming a gold standard. Methods? We applied a Bayesian version of latent class analysis to compare the results of multiple assessments from different study settings reported in the literature. Results? The results showed that this HI test has nearly perfect accuracy (i.e. 988% sensitivity and 995% specificity). It performed well in both chickens and turkeys and yet was less accurate in experimentally infected poultry, compared to naturally infected. Blocking ELISA and the indirect immunofluorescence assay also performed very well. Conclusions? Given its very high Se and Sp, the HI test may be effectively considered a gold standard. In the framework of LPAI surveillance, where large numbers of samples have to be processed, the blocking ELISA could be a valid alternative to the HI test, in that it is almost as sensitive and specific as the HI test yet quicker and easier to automate. was calculated as the proportion of MC samples for which Lometrexol disodium [DIC?=?1262] /th th colspan=”4″ align=”left” valign=”bottom” rowspan=”1″ [DIC?=?1273] /th /thead TestSe95%PCISp95%PCISe95%PCISp95%PCIHI988[960; 100]995[984; 100]990[964; 100]996[985; 100]iIFA981[940; 999]963[918; 994]966[933; 987]940[906; 965]bELISA993[980; 100]976[952; 998]993[979; 100]974[950; 997]cELISA_C*708[628; 780]646[480; 800]707[627; 780]643[480; 794]cELISA_T**968[916; 993]220[52; 524]968[916; 993]216[52; 510]NP\ELISA921[860; 963]575[422; 726]932[879; 968]630[489; 766]AGP662[564; 751]963[819; 999]662[565; 751]963[819; 999] Open in a separate window *cELISA_C?=?cELISA used for chickens. **cELISA_T?=?cELISA used for turkeys. The use of useful priors around the Se and Sp of the iIFA and the NP\ELISA did not affect the posterior estimates of any of the parameters (Table?4). Furthermore, the DIC slightly favoured the model with uninformative priors (DIC?=?1262 for the model with uninformative priors, compared to 1273 for the model with informative priors). The estimated Se and Sp of the HI test derived from the two studies in which the HI test and the bELISA were evaluated 16 , 17 were Eng very close to the estimates obtained when including all of the studies (Table?5). Table 5 Posterior median and 95% posterior credible intervals (PCI) of the sensitivity (Se) and specificity (Sp) of the HI test and bELISA, considering using only the two studies in which these tests were evaluated 16 , 17 thead valign=”bottom” th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ Test /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ Se /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ 95%PCI /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ Sp /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ 95%PCI /th /thead HI979[951; 999]995[982; 100]bELISA994[980; 999]982[955; 999] Open in a separate window The results of the stability analysis of the HI test are reported in Table?6. The HI test appeared to perform the same for the two species considered: the estimated Se and Sp of HIchicken did not differ significantly from the estimates of HIturkey (POPR?=?03539 for Se and POPR?=?03597 for Sp). However, the HI test was more accurate in naturally infected birds than in experimentally infected birds: POPR?=?0022 for Se of HInatural? ?Se of HIexperimental and POPR?=?00002 for Sp of HInatural? ?Sp of HIexperimental. Table 6 Posterior median and 95% posterior credible intervals (PCI) of the sensitivity (Se) and specificity (Sp) of the HI test, assuming different performance by species (HIchicken and HIturkey) and source of contamination (HInatural and HIexperimental) thead valign=”bottom” th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ /th th colspan=”4″ align=”left” valign=”bottom” rowspan=”1″ Test evaluated /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ Null hypothesis (H0) /th th align=”left” valign=”bottom” rowspan=”1″ colspan=”1″ POPR* /th /thead SpeciesHIchicken HIturkey em ? /em Se989[961; 100]981[926; 999]Se HIchicken? ?Se HIturkey 03539Sp995[981; 100]991[960; 100]Sp HIchicken? ?Sp HIturkey 03597Source of infectionHInatural HIexperimental ??Se993[970; 100]911[851; 989]Se HInatural? ?Se HIexperimental 00222Sp996[985; 100]812[595; 986]Sp HInatural? ?Sp HIexperimental 00002 Open in a separate window *POPR, Bayesian posterior probability. Discussion Using latent class analysis and published data, we estimated the accuracy of the HI test and six other diagnostic assays in detecting AIV antibodies, without making reference to a gold standard. Because the HI test is commonly considered the gold standard for type\specific AIV antibody Lometrexol disodium detection, its performance has rarely been questioned. Compared to the only previous study in which the accuracy of the Lometrexol disodium HI test was estimated for poultry, 9 we found a similar Se and a much higher Sp, as well as much narrower credible intervals. This comparison might seem unfair, because we included the data of the previous study in our model. However, according to a sensitivity analysis (data not shown), the estimated Se and Sp Lometrexol disodium of the HI test remained basically unvaried when excluding the study from the analysis, suggesting that the data from such study are consistent with those of the other studies. This study is the first attempt to estimate the Se and Sp of the HI test based on data collected in different study settings. This allowed us to investigate possible sources of variation in the performance of the HI.