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Table 2 Diagnostic agreement between PCR assays and parasitological methods

From: Evaluation of a polymerase chain reaction assay for the diagnosis of bovine trypanosomiasis and epidemiological surveillance in Bolivia

  Area
Province Guarayos Sara
  Concordant results Kappa values+ Concordant results Kappa values
  Positives Negatives   Positives Negatives  
TvPCR vs Thin smears 9 232 0.622 0 233 -0.007
TvPCR vs MHCT 5 233 0.389 0 235 -0.007
TePCR vs MHCT* 2 238 0.245 0 230 -0.020
  1. * There is no agreement analysis between TePCR and thin smears because T. evansi was not diagnosed in the smears observations. + Arbitrary bench marks for evaluating kappa values are : >0.81: almost perfect agreement; 0.61 – 0.80: substantial agreement; 0.41 – 0.60: moderate agreement; 0.21 – 0.40: fair agreement; 0 – 0.20: slight agreement; 0: poor agreement and negative results: no agreement. Kappa rages from 1 (complete agreement) to 0 (agreement is equal to that expected by chance) [24]. PCR shows a statistical agreement with parasitological techniques only in Guarayos. There was no agreement between PCR and the parasitological methods in Sara.