Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis.
An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.
Wood
P R
PR
CSIRO Division of Animal Health, Animal Health Research Laboratory, Private Bag No 1, Parkville, Victoria.
Corner
L A
LA
Rothel
J S
JS
Baldock
C
C
Jones
S L
SL
Cousins
D B
DB
McCormick
B S
BS
Francis
B R
BR
Creeper
J
J
Tweddle
N E
NE
D000818:Animals; D001315:Australia; D002020:Buffaloes; D002417:Cattle; D005189:False Positive Reactions; D007371:Interferon-gamma / Q000097:blood*; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods / Q000662:veterinary*; D014380:Tuberculosis, Bovine / Q000175:diagnosis*
D007371:Interferon-gamma