Interpretation of results
For specific questions about the interpretation of results you may contact our scientific staff, who will be glad to help you. In the following you will find some general information regarding the interpretation of the results:
"negative" results
As a general rule negative results do not exclude a virus infection.
Possible reasons for false negative results:
- Choice of samples (unsuitable samples, improper extraction time,...)
- Sampling (unsterile samples, unsuitable culture medium,...)
- Mailing of samples (excess of transport time,...)
- Limitations of diagnostic methods (sensitivity, test errors)
"positive" results
A positive test result always has to be interpreted in the context with the anamnesis and clinical signs.
Possible reasons for false positive results:
- Subclinical infections,
- Ubiquitous germs,
- Antibody titre caused by vaccination or maternal antibodies
Interpretation of serological results:
- Paired serum samples taken at an interval of 2 to 4 weeks will in most cases allow the identification of an acute or subacute infection. A significant rise in antibody titres (sero conversion) is indicative in this respect.
- Discrimination between antibodies due to vaccination or due to infection with a field virus strain will not be possible in most cases. For this reason it is essential to determine the animal's vaccination status before sampling.
- For most virus-induced diseases thresholds for protective immunity by antibody titres are not defined. This information can only be obtained by animal experiments ("challenge-tests"). The interpretation of the test result generally only shows whether the animal has responded to the vaccination with a low, moderate, high antibody titre or not at all. Exceptions to this rule are rabies and canine parvovirus where thresholds have been defined.