One of the reasons why FIP (Feline Infectious Peritonitis) is terrible is that there is no simple diagnosis method (unlike canine distemper, small, although not easy to treat, but at least it is easy to know whether it is sick). ELISA (enzyme-linked immunosorbent test), IFA (immunofluorescence detection), and Virus-neutralization test (virus neutralization test) can only detect whether there are antibodies to coronavirus in cats but cannot distinguish whether the detected antibodies are caused by the type of coronavirus that can cause FIP in cats is produced.
These tests give us antibody titers (a measure of antibody levels), which are also not a valid indicator of whether a cat is infected with FIP or protected by antibodies. In other words, a high antibody titer neither indicates that the cat is infected with the FIP virus, nor does it guarantee that the cat will not get FIP in the future.
So does a negative result always mean that the cat is not infected with FIP? Not necessarily, a negative result usually means that the cat is not infected with the coronavirus (so of course there is no chance of being infected with FIP), but if the cat has been infected with FIP, the negative result may be because the infection time is very short, and the body has not produced enough antibodies for detection. , or the cat no longer has the ability to produce antibodies, or the existing antibodies are all kidnapped by the virus, so the test cannot detect it.
It’s not that the tests mentioned above are useless, but I want to tell you that a single test often cannot get an accurate answer. Clinically, doctors will comprehensively consider many indicators, the following three are particularly important:
very low white blood cell count (blood test)
Positive high titer antibody test result
significantly elevated globulin
If all three conditions are met, there is an 89% chance that the cat will get FIP. If one of the conditions is not met, the cat will have a 99% chance of not getting FIP. Medicine is still developing. Although there is no 100% diagnosis, it can help doctors to a large extent to carry out treatment. If the cat has ascites or pleural effusion (which may be wet FIP), then analyze the fluid and if the gamma globulin ratio exceeds 32%, then the cat has an almost 100% chance of having FIP If the ratio of albumin (Albumin) exceeds 48% or the ratio of albumin to globulin is greater than 0.81, then it is almost 100% sure that the cat does not have FIP.
Of course, the most reliable test is to use biopsy to obtain infected tissue and let a pathologist make a final diagnosis.