DETECTION EFFICIENCY OF MASTITIS SCREENING TESTS

Abstract

Summary A comparison of the detection efficiency of five screening tests for mastitis was made by correlating test results with results of a specific laboratory standard based on a direct leukocyte count and/or the culturing of infectious organisms on the same samples of milk. Since the screening tests are “indirect” or non-specific in nature, the measure of effectiveness took into consideration not only the per cent detected as compared to that detected by the laboratory method, but also the per cent of readings which were false positives. Both per cent detection and per cent false positives increased with increasing test sensitivity. The level of detection at which the per cent of false positives began to increase rapidly was chosen as the optimum efficiency for each type of test. This optimum efficiency correlated with the presence of mastitis as follows: California Mastitis Test 69.5%; Whiteside Test 65.5%; Filter Disk Test 45.0%; Catalase Test 43.8%; Strip Plate Test 4.7%.