Table 6.
Diagnostic test issues 1.
| Overlooked Facts | Consequences (Common Mistakes) |
|---|---|
| In vitro, smooth brucellae readily generate rough mutants. | For buffered agglutination 2 and complement fixation tests, false and inconsistent results are given. For all tests, strict quality control is necessary. |
| iELISA, cELISA and FPA require validation for local conditions. | Incorrect seroprevalence (use of manufacturer’s cut-offs, mostly of an unknown basis). |
| Sub-optimal sensitivity of cELISAs and SAT. | Seroprevalence sub-estimation. |
| Assays used in brucellosis-free countries for surveillance are not the best choice everywhere. | Needless infrastructure demands and costs. |
| Buffered acid pH agglutination tests 1 match iELISAs in terms of sensitivity/specificity. | It is overlooked that these agglutination tests are almost ideal under many circumstances (the misconception that these tests are negatively affected by prozones and are highly unspecific). |
| Misleading understanding of “Confirmatory tests”. | Incorrect seroprevalence estimations (e.g., RBT confirmed by iELISA, cELISA, FPA or complement fixation in the absence of S19 vaccination). |
| The milk-ring test only works in cattle (Bos taurus). | Incorrect prevalence estimations in small ruminants, buffaloes, and camels. |
| Molecular tests (PCR) require strict validation. | Unknown false-positive/negative score (identity between analytical and diagnostic parameters; “validation” in poorly defined populations (no true Brucella-free and no gold-standard positive controls) or in experimentally infected animals. |