Page 1443 - Veterinary Immunology, 10th Edition

reactions. If this cut-off point is adjusted downward, so that the
VetBooks.ir criterion for a positive test is made less strict, the number of false-

positive results will increase, but there will also be a decrease in the
number of false-negative results. In practice, therefore, highly

sensitive tests tend to be relatively nonspecific, and highly specific
tests are generally insensitive. The establishment of the cut-off point
in reading test results and, from this, the sensitivity and specificity
of a test are determined both by the requirements of the test

procedure and by the significance of false-positive and false-
negative reactions.

FIG. 42.32 Schematic diagrams depicting the errors associated
with immunological tests. The top diagram (A) depicts an ideal test
in which there is no ambiguity in interpreting test results. The bottom
diagram (B) depicts a more typical test in which an arbitrary line
must be used to separate positive from negative results. By moving

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