Louping Ill Antibody*

*This test is subcontracted

Pricing: 1-9 samples = £15.85 per sample; 10+ samples = £13.85 per sample

Interpretation of Louping Ill Serology based on Haemagglutination-Inhibition (HAI) Test
An HAI test can be carried out on serum from any mammalian species, but the interpretation offered below specifically refers to cattle, sheep and goats. If the submitted sample(s) were from a non-ruminant species please contact the laboratory for further interpretation.
The HAI test is conducted at dilutions of 1 in 10, 1 in 20 and 1 in 40.
- Samples with a titre of 1 in 10 or less are considered negative.
- Samples with a titre of 1 in 20 are considered suspicious
- Samples with a titre of 1 in 40 or greater are considered positive

Serum is tested for HAI antibody both unheated and after heating to 64ºC for 30 minutes. The HAI test is performed at dilutions up to at least 1/640 for screening samples and 1/5120 for diagnostic samples. A fourfold or greater reduction in titre in the heated sample indicates that much of the antibody is due to IgM, from which it many be inferred that the serum has been collected from a recently infected animal. However as IgG may largely replace IgM before clinical signs are manifest, the absence of detectable IgM antibody in positive sera does not preclude the possibility of recent louping ill virus infection. Titres >1/640 probably indicate recent infection.