Objective—To evaluate diagnostic utility of a commercially
available immunoassay for assessing adequacy
of passive transfer of immunity in neonatal
Procedure—Blood and serum samples were obtained
from the calves prior to 2 weeks of age. The immunoassay
was performed, along with refractometry and an
18% sodium sulfite turbidity test. Serum IgG concentration
was determined with a radial immunodiffusion
assay. Sensitivity and specificity of the immunoassay,
refractometry, and the sodium sulfite test were calculated
by comparing results with results of the radial
Results—Sensitivity and specificity of the blood IgG
immunoassay were 0.93 and 0.88, respectively, compared
with 1.00 and 0.53 for the sodium sulfite test.
For refractometry, sensitivity and specificity were 0.71
and 0.83, respectively, when a serum total solids concentration
of 5.2 g/dl was used as the cutoff between
positive and negative test results.
Conclusions and Clinical Relevance—Results suggest
that the immunoassayperforms well in detecting
calves with inadequate passive transfer of immunity.
(J Am Vet Med Assoc 2002;220:791–793)