I: Glossary of Terms. 6 th ed. Paris, France: WOAH; Page 3

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1 IDEXX SNAP* BVD Test 2010 IDEXX Laboratories, Inc. All rights reserved IDEXX and Test With Confidence are trademarks or registered trademarks of IDEXX Laboratories, Inc. or its affiliates in the United States and/or other countries. The IDEXX Privacy Policy is available at idexx.com.

2 The IDEXX SNAP* Bovine Virus Diarrhea (BVD) Antigen Test Kit (SNAP* BVD) is an enzyme-linked immunosorbent assay (ELISA) designed to detect the presence of bovine viral diarrhea virus (BVDV) antigen in immunotolerant, persistently infected bovines, using serum and both large or small ear-notch tissue (tissue measuring at least 1 cm along one side [large] or at least 2 3 mm in diameter [small]). The test uses IDEXX s proprietary format, the SNAP device, which provides reversible chromatographic flow of the sample and sequential flow of wash and enzyme substrate. Color develops in spots on the flow matrix and results are read visually. The IDEXX SNAP* BVD Test Kit is based on the detection of the E rns (gp44 48) glycoprotein of the BVD virus. Positive results from this assay are valid for calves of any age. Calves less than 3 months of age usually have high levels of circulating anti-bvd colostral antibodies. Colostral antibodies have limited interference with BVD antigen detection from ear-notch tissue samples, which allows testing of cattle of any age with this sample type. However, because serum samples allow for maternal antibody interference, customers using the serum sample type should confirm negative results with a second test after the calf has reached three months of age.

3 I:GlossaryofTerms The following definitions have been taken from the Glossary of Terms section of the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 1 and may be used to describe the assay s performance characteristics in this validation report. Repeatability Level of agreement between replicates of a sample (tested multiple times with individual SNAP devices) within a given laboratory. Reproducibility Ability of a test method to provide consistent results when applied to aliquots of the same sample tested by the same test method in different laboratories. Sensitivity(analytical) Synonymous with Limit of Detection, or the lowest amount or level of the analyte that can be detected (end-point dilution analysis) with a defined certainty. Analytes may include antibodies, antigens, nucleic acids, live organisms, etc. Sensitivity(diagnostic) The proportion of reference animals (whose condition or disease status has been determined as positive) that are identified as positive in the assay. Negative test results from animals characterized as positive are considered false negatives. Specificity(analytical) The degree to which the assay discriminates or distinguishes between the intended target analyte and other components in the sample matrix. The rate of false positivity is expected to be lower with greater analytical specificity. Specificity(diagnostic) The proportion of reference animals (whose condition or disease status has been determined as negative) that are identified as negative in the assay. Positive test results from animals characterized as negative are considered false positives. 1World Organization for Animal Health (WOAH), Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 6 th ed. Paris, France: WOAH; Page 3

4 II:Repeatability Purpose: Procedure: ToevaluatethevariabilityofSNAPBVD. Anegativesampleandtwopositivesamplesrepresentingapositive andalower levelpositivesamplewereeachtestedonten(10) devices.testingwithsnapbvdwasconductedaccordingtothe standardassayprotocolforserum.densigraphreadingsforeachspot (PositiveControl,PC;NegativeControl,NC;and,Sample,BVD)were obtainedands N(sample negative)andthepercentcoefficientof variation(%cv)valueswerecalculatedforeachsample. Results/ Conclusions: Densigraphreadings,S Nand%CVvalues,aswellasvisual interpretationsforthesamplespot(bvd)areshowninfigures1a,1b, and1c. The%CVvaluesforthedensigraphreadingsforallthreespots,aswell asthes Nvalue,areallless8%.Thesevaluesindicategooddevice todevicerepeatabilityforsnapbvd. Figure1a. Device to DeviceVariabilityofSNAPBVD:BVD NegativeSample Page 4

5 Figure1b. Device to DeviceVariabilityofSNAPBVD:Lower LevelBVD PositiveSample Figure1c. Device to DeviceVariabilityofSNAPBVD:BVD PositiveSample Page 5

6 III:DiagnosticSensitivityandSpecificity SmallEar NotchTissueSamples Purpose: Procedure: Results/ Conclusions: ToevaluatethesensitivityandspecificityofSNAPBVDbycomparison tothetruestatusofsamples,characterizedaspositiveornegativeby theidexxbvdvag/serumplustest(eu ELISA)andRT PCR(orViral Isolation,VI). Atotalof236ear notchspecimenswerecollectedfromawidevariety ofgeographiclocationsthroughouttheu.s.therewereatotalof106 specimenscharacterizedasbvdpositive.theremaining130 specimenswerecharacterizedasbvdnegative.samplesweretested onsnapbvdusingthesmallear NotchProtocolandreadvisually. Densigraphreadings,S Nvalues,aswellasvisualinterpretationsfor thesamplespot(bvd)wererecorded.theresultsobtainedwith SNAPBVDwerecomparedtothetruestatusofthesamplesasshown infigure2.snapbvddemonstratesexcellentagreementwiththeeu ELISAandbothRT PCRandVI. Figure2. SmallEarNotch:DiagnosticSensitivityandSpecificity Page 6

7 IV:DiagnosticSensitivityandSpecificity LargeEar NotchTissueSamples Procedure: Protocol: Results/ Conclusions: ToevaluatethesensitivityandspecificityofSNAPBVDbycomparison tothetruestatusofsamples,characterizedaspositiveornegativeby theidexxbvdvag/serumplustest(eu ELISA)andRT PCR(orViral Isolation,VI). Atotalof416ear notchspecimenswerecollected.specimenswere obtainedfromawidevarietyofgeographiclocationsthroughoutthe U.S.SamplesweretestedonSNAPBVDusingtheLargeEar Notch Protocolandreadvisually.(Note:Oneofthe416sampleswasnot testedontheeu ELISA.) Densigraphreadings,S Nvalues,aswellasvisualinterpretationsfor thesamplespot(bvd)wererecorded.theresultsobtainedwith SNAPBVDwerecomparedtothetruestatusofthesamplesas determinedbytheeu ELISA(showninFigure3a)orby RT PCRorVI(showninFigure3b).SNAPBVDdemonstratesexcellent agreementwiththeeu ELISAandexceptionalperformancerelativeto RT PCRandVI. Figure3a. LargeEarNotch:DiagnosticSensitivityandSpecificity(RelativetoEU ELISA) Page 7

8 Figure3b. LargeEarNotch:DiagnosticSensitivityandSpecificity (RelativetoRT PCR,VI) Page 8

9 V:DiagnosticSensitivityandSpecificity SerumSamples Procedure: Protocol: Results/ Conclusions: ToevaluatethesensitivityandspecificityofSNAPBVDbycomparison tothetruestatusofsamplescharacterizedaspositiveornegativeby theidexxbvdvag/serumplustest(eu ELISA)andRT PCR(orViral Isolation,VI). Atotalof426serumspecimenswerecollected.Specimenswere obtainedfromawidevarietyofgeographiclocationsthroughoutthe U.S.SamplesweretestedonSNAPBVDusingtheSerumProtocoland readvisually. Densigraphreadings,S Nvalues,aswellasvisualinterpretationsfor thesamplespot(bvd)wererecorded.theresultsobtainedwith SNAPBVDwerecomparedtothetruestatusofthesamplesas determinedbytheeu ELISA(showninFigure4a)orby RT PCRorVI(showninFigure4b).SNAPBVDdemonstratesexcellent agreementwiththeeu ELISA.SNAPBVDperformancewithserum samplesdemonstrateslowersensitivityrelativeto RT PCRorVI. Figure4a. Serum:DiagnosticSensitivityandSpecificity(RelativetoEU ELISA) Page 9

10 Figure4b. Serum:DiagnosticSensitivityandSpecificity(RelativetoRT PCR,VI) Page 10

11 VI:GenotypeDetectionCapabilities Procedure: Protocol: ToevaluatetheabilityofSNAPBVDtodetectvariousgenotypesof BVD. SpecimensusedtoevaluatethesensitivityandspecificityofSNAP BVDwithserumandlargeearnotcheswereusedforthisstudy.Ofall specimenstestedintheserumandlargeear notchstudies,426and 416(respectively),atotalof232specimensweregenotyped. Specimensweresenttoaccreditedveterinarydiagnosticlabs. Genotypesweredeterminedbysequenceanalysisofthe 5 untranslatedregion(5 UTR)oftheBVDgenome.Sampleswere testedonsnapbvdusingthelargeear NotchorSerumProtocols andreadvisually. Results/ Conclusions: Ofthe232specimensthatweresentforgenotyping,228specimens weredetectedbysnapbvd,asshowninfigure5.ofthefour specimensnotdetectedbysnapbvd,therewasnodemonstrationof adetectiongaprelatedtoanyspecificgenotype.therefore,snapbvd hasbeenshowntobeabletodetectbvdgenotypes1a,1b,2(2a,2b). Figure5. DetectionCapabilityofSNAPBVDwithVariousGenotypes Page 11

12 Page 12 VI:MaternalAntibodyInterference Procedure: ToevaluatetheabilityofSNAPBVDtodetectBVDantigeninserum takenfromcalvesthathaveingestedcolostrum. Protocol: BloodfromnewbornEuropeancalvespersistentlyinfectedwithBVD wasobtainedatbirth(priortoingestionofcolostrum)and throughoutseveralmonths,postpartum.samplesweretestedon SNAPBVDusingtheSerumPprotocolandreadvisually. Results/ Conclusions: Usingborderlinepositiveresults(resultsthatmaybecategorizedas visually +/ ),BVDantigencanbedetectedbySNAPBVDatlessthan 30dayspost partum.however,usingonlystronglypositiveresults, thediagnosticgaporwindowfordetectionofbvdantigenbysnap BVDislessthan50dayspostpartum.Becauseofthesmallnumberof BVD PIcalvestested,itisrecommendedthatifserumisbeingused, calvesbeatleast3monthsoldpriortotesting.refertofigure6. Ifear notchspecimensareusedfortesting,interferencebymaternal antibodiesisnotexpectedtooccur.therefore,calvesofanyagecan betestedusingear notchtissue.

13 Figure6. DetectionCapabilityofSNAPBVDwithNewbornCalvesIngestingColostrum Page 13