Document - FAVV

Evaluation of immunoassay kits for determination of ochratoxin A in cerealsTable 33: Calculation of false positives/negatives & true positives/negativesSamples spiked above the cut-off value Samples spiked below the cut-off value Total numberPositive TP (True positive) FP (False positive) TP +FPNegative FN (False negative) TN (True Negative) FN + TNTotal number TP + FN FP + TN N =TP + FN +FP +TNScreening methods for OTA should be compliant to the following criteria 67 :Sensitivity should be 100% when exceeding the action limitSpecificity should be > 95% when exceeding the action limitThe Europroxima kit is compliant to these requirements (Table 32).3.2.4.4 Relative accuracy after confirmation of screening materials against reference methodThe Calculation of Relative Accuracy, Relative Sensitivity and Relative Specificity starting from a contingency table issummarized in Table 34 andTable 35.Table 34: Contingency tableReference method positive Reference method negative Total number of samplesPositive PA (Positive agreement) PD ( Positive deviation) PA+PDNegative ND (Negative deviation) NA (Negative agreement) ND+NATotal number of samples PA+ND PD+NA PA+NA+PD+NDTable 35: Calculation of Relative Accuracy, Relative Sensitivity and Relative SpecificityRelative Accuracy RA (%) Relative Sensitivity SE (%) Relative Specificity SP (%)(PA+NA)/(PA+NA+PD+ND) PA/(PA+ND) NA/(PD+NA)Table 36: Relative accuracy, relative sensitivity and relative specificityEuroproximaR-BiopharmRelative AccuracyRA (%)Relative SensitivitySE (%)Relative SpecificitySP (%)Relative AccuracyRA (%)Relative SensitivitySE (%)Relative SpecificitySP (%)Rye 100% 100% 100% NS NS NSBarley 100% 100% 100% NS NS NSCoffee 100% 100% 100% NS NS NSWine 91% 100% 100% NS NS NS67 Guidelines and acceptance criteria for analysis methods mycotoxins (DON, ZEN and OTA) in raw materials for animal feed, Productschapdiervoeder (PDV), Quality series n o 96, 2004CODA-CERVA | Administrative evaluation 3-33