Cat with FIP:
- Albumin:globulin ratio (A/G ratio): This is a ratio of the albumin and globulin levels in the blood. A study of 100 cats with FIP and 100 cats without FIP found that 90% of cats with FIP had an A/G ratio of 0.4 or less, while only 10% of cats without FIP had an A/G ratio of 0.4 or less. This means that a cat with an A/G ratio of 0.4 is 9 times more likely to have FIP than a cat with a normal A/G ratio.
- Low albumin level (hypoalbuminemia): Albumin is a protein that helps to keep fluid in the bloodstream. A low albumin level can indicate that there is protein loss from the body, which can occur in FIP due to inflammation and damage to the kidneys and liver.
- High globulin level (hyperglobulinemia): Globulins are proteins that play a role in the immune system. A high globulin level can indicate that the body is fighting an infection, which can occur in FIP.
- Elevated white blood cell count (leukocytosis): Leukocytosis can indicate that the body is fighting an infection, which can occur in FIP.
- Elevated liver enzymes: Liver enzymes can be elevated in FIP due to inflammation and damage to the liver.
- Low red blood cell count, anemia: Anemia is a decrease in the number of red blood cells or the amount of hemoglobin in the blood. Anemia can occur in FIP due to inflammation and damage to the bone marrow. 30% to 50% of cats with FIP will also have anemia.
- High neutrophil count: High neutrophil count can be one of the bloodwork abnormalities seen in cats with FIP. Neutrophils are a type of white blood cell that is the body’s first line of defense against infection. A high neutrophil count can indicate that the body is fighting an infection, which can occur in FIP.
- High protein: Also known as hyperproteinemia, can play a part in determining FIP in cats because it is one of the most common bloodwork abnormalities seen in this disease.
- High bilirubin: Bilirubin is a yellow pigment that is produced when red blood cells break down. It is normally filtered from the blood by the liver and excreted in the bile. However, if the liver is not functioning properly or if there is excessive red blood cell breakdown, bilirubin levels in the blood can become elevated.
Cat without FIP:
- Albumin level in the normal range
- Globulin level in the normal range
- White blood cell count in the normal range
- Liver enzymes in the normal range
- Red blood cell count in the normal range
- Hemoglobin level in the normal range
- Neutrophil count in the normal range
- Protein level in the normal range
- Bilirubin level in the normal range
Bloodwork in general is not very accurate in determining if a cat has FIP. The most common bloodwork indicators of FIP, such as hyperglobulinemia and lymphopenia, can also be caused by other diseases. Therefore, a definitive diagnosis of FIP cannot be made based on bloodwork alone, though it is a helpful piece of the puzzle.
However, one study found that a combination of three blood tests, including a low lymphocyte count, a high blood globulin level, and a positive coronavirus antibody test, had a 94% chance of detecting FIP in cats. But even this combination of tests is not perfect, as there is still a 6% chance of a false negative result.
The most accurate way to diagnose FIP is through a biopsy of affected tissues. However, biopsies can be invasive and risky, and they are not always possible to obtain. Moreover, analysis of a tissue sample can take weeks to receive results, and therefore not viable with a disease that progresses as quickly as FIP.
Another way to diagnose FIP is through a PCR test of abdominal fluid or other effusions. PCR tests are highly sensitive and specific for FIP, but they are not always available or affordable.
In general, bloodwork is not a reliable way to diagnose FIP. If your veterinarian suspects that your cat may have FIP, they may recommend additional tests, such as a biopsy or PCR test, to confirm the diagnosis.
Here are some additional things to keep in mind about bloodwork and FIP:
- Bloodwork may be helpful in identifying cats that are at risk of developing FIP, such as cats that are exposed to the FIP virus or that have other underlying diseases.
- Bloodwork can also be helpful in monitoring the progression of FIP in cats that have already been diagnosed.
- Newer blood tests, such as the FIP-Ab ELISA test, are being developed to improve the accuracy of bloodwork in diagnosing FIP. However, these tests are not yet widely available.
If you have any concerns about your cat’s health, please talk to your veterinarian. They can help you to interpret your cat’s bloodwork results and determine if any further testing or treatment is necessary.
It is important to note that not all cats with FIP will have abnormal bloodwork results. Additionally, the bloodwork abnormalities seen in FIP can be caused by many other conditions. Therefore, bloodwork alone cannot be used to definitively diagnose or rule out FIP.
