Screening badgers (Meles meles) for Mycobacterium bovis infection by using multiple applications of an ELISA

The current indirect ELISA used to evaluate whether live badgers are infected with Mycobacterium bovis has a low sensitivity (40-7 per cent), but a relatively high specificity (94-3 per cent). The low sensitivity of the test makes the diagnosis unreliable, but its sensitivity can be increased by using multiple tests. Two multiple testing procedures (involving up to three sequential tests) were investigated. A procedure in which two positive results were required from three tests before an animal was declared positive resulted in a lower sensitivity, but a higher specificity than the single test (38 and 98 per cent respectively). A more rigorous procedure, in which only one positive result was required from three tests, resulted in a marked increase in sensitivity but a slight reduction in specificity (79-5 and 83-1 per cent respectively) when compared to the single test.