  From 1994, we began to use ELISA (Enzyme Linked Immunosorbent Assay) in the
diagnosis of PCP. This is aELISA for capturing antigens (PACE) possibly
contained in the samples. The advantage of this test comes from the fact that
it is completelyindependent of cell cultures. In addition, it is fast: the
result can be obtained in less than 36 hours. A study of its
standardizationcarried out in Australia gave a sensitivity (Se) of 99%, a
specificity (Sp) close to 100% and a negative predictive value (NPV) of 99.7%.
Due to its high specificity, the test gives a negative result to all true
negatives, in other words, the negatives of the test correspond to thetrue
negatives. A variant of the capture ELISA, the CTB-ELISA or complex trapping
blocking ELISA allows the quantity of antibodies to be measureddirected against
the non-structural protein, p80 (or NS3), contained in animal sera. Evaluation
of the level of anti-NS3 antibodiesconstitutes an excellent assessment of the
level of neutralizing antibodies because the correlation coefficient between
these two types of antibodies, the firstobtained by CTB-ELISA, and the second
by serum neutralization (VNT), is very high (r = 0.98).The two tests being
capable, one of detecting pestiviral antigens and the other of measuring
antibodies specific to each of thegroups, constitutes an excellent tool for the
qualitative control of anti-CSF vaccine.
