A study mentioned by IDEXX on their productinformation sheet shows the sensitivity and specificity of the SNAP and SpeccPL tests to be 93% and 78% (McCord K.
et. al, 2012) respectively, howeversince this relates to one of their own products we compared this to otherpublished data. A separate publication quoted the sensitivity andspecificity of the SNAP cPL test to be 82% and 59% respectively. This is acloser comparison to the values we calculated; 83. 33% for sensitivity and51. 72% for specificity. Both the values we calculated and those published werelower than the values reported by IDEXX, in particular the specificity is ~20%lower than quoted. Compared to the SNAP test, the Spec cPL test was reported ashaving a sensitivity and specificity of 70% and 77% respectively.
This compareswell with our calculated values for Spec cPL sensitivity and specificity whichwere; 72. 22% and 79. 31% respectively. The accuracy also quoted in this studywas 66% for the SNAP cPL and 75% for the Spec cPL test (Haworth MD, et. al, 2014). This compared to our calculated results (SNAP: 63.
83% and Spec: 76. 60%)closely, with only slight differences between the values. Two studies, the first of which was carried outon 84 dogs, reported their findings of sensitivity of the Spec cPL diagnostictest to be between 86-94% (on a cut off value of 200? g/L) (Xenoulis, P. G. et. al, 2016).
This is quite a difference in comparison to our calculated value for thesensitivity of Spec cPL (72. 22%). They also reported the sensitivity of theSNAP cPL test as ranging between 91-94%, which is also much higher than weexpected (83. 33%). The second study, only contained 38 dogs, however theresults compared more closely with the our calculated values, previouslymentioned. Spec sensitivity was published as 70% and SNAP sensitivity as 82% (Xenoulis, P. G.
et. al, 2016), compared to 72. 22% and 83.
33% respectively. Overall, I think some publications are morereliable than others. The information released by IDEXX may be less accuratethan reviewed data since they can use data to sell their product (SNAP cPLTest). Tests including more patients would also be assumed to be more accurate, however there are examples of studies which quote similar values to IDEXXthemselves which makes it difficult to know which studies can be trusted. However, since all studies came up with values within roughly the same ranges, it can be said that the methods they are using to analyse such diagnostic testsmust be somewhat accurate.