What does bloodwork look like with FIP?

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The bloodwork of a cat with Feline Infectious Peritonitis (FIP) typically shows a complex picture, often including abnormal protein levels, especially a low albumin to globulin (A:G) ratio, anemia, and elevated white blood cell counts. Interpreting these results correctly is crucial for timely diagnosis and treatment.

Introduction: The FIP Bloodwork Puzzle

Feline Infectious Peritonitis (FIP) is a devastating disease in cats caused by a mutated form of feline coronavirus (FCoV). While there’s no single blood test that definitively diagnoses FIP, a thorough analysis of bloodwork, in conjunction with clinical signs and other diagnostic tests, provides invaluable clues for veterinary professionals. Understanding what does bloodwork look like with FIP is paramount for early suspicion and subsequent diagnostic investigations.

Understanding FIP and its Impact on Blood

The mutated feline coronavirus, responsible for FIP, causes a systemic inflammatory response that affects multiple organs. This widespread inflammation leads to various changes in the cat’s blood parameters, making the interpretation of bloodwork a complex but essential part of the diagnostic process. Two main forms of FIP exist:

Effusive (Wet) FIP: Characterized by the accumulation of fluid in the abdomen (ascites) and/or chest (pleural effusion).
Non-Effusive (Dry) FIP: Presents with granulomas (inflammatory masses) in various organs, often without significant fluid accumulation.

The bloodwork findings can vary slightly depending on the form of FIP and the organs primarily affected.

Key Bloodwork Parameters Affected by FIP

Several bloodwork parameters are commonly affected in cats with FIP. Analyzing these changes helps veterinarians to form a stronger suspicion of the disease. Here’s a breakdown of the key findings:

Albumin and Globulin Levels: The most consistent finding is a low albumin to globulin ratio (A:G). Albumin levels are often low due to protein loss and decreased liver function, while globulin levels are elevated due to the body’s immune response. A ratio below 0.8 is highly suggestive of FIP.
Complete Blood Count (CBC):
- Anemia: Mild to moderate non-regenerative anemia (bone marrow is not producing enough red blood cells) is common.
- White Blood Cell Count: Can be variable. Often elevated (leukocytosis) due to an increase in neutrophils (neutrophilia), but sometimes normal or even low (leukopenia).
- Lymphocyte Count: Can be low (lymphopenia) in some cases, indicating immune system suppression.
Biochemistry Panel:
- Liver Enzymes (ALT, AST, ALP, GGT): Elevated in some cases, especially in dry FIP affecting the liver.
- Bilirubin: May be elevated, indicating liver dysfunction or bile duct obstruction.
- Kidney Values (BUN, Creatinine): Can be elevated if FIP affects the kidneys.
- Total Protein: Often elevated due to increased globulins.

Interpreting the Results: The Importance of Context

It’s crucial to remember that no single bloodwork finding is definitively diagnostic for FIP. Many other conditions can cause similar changes in blood parameters. Therefore, the results must be interpreted in the context of:

Clinical Signs: Fever, lethargy, anorexia, weight loss, abdominal distension, neurological signs (especially with dry FIP).
Age: FIP is most common in young cats (under 2 years old) and geriatric cats.
Exposure History: Cats from multi-cat households or shelters are at higher risk.
Other Diagnostic Tests: Fluid analysis (if effusion is present), histopathology (tissue biopsy), PCR testing, and imaging (X-rays, ultrasound).

Common Mistakes in Bloodwork Interpretation

Misinterpreting bloodwork results can lead to delayed diagnosis and treatment. Some common mistakes include:

Relying solely on bloodwork for diagnosis without considering clinical signs and other diagnostics.
Ignoring the A:G ratio or failing to calculate it accurately.
Dismissing normal bloodwork results despite strong clinical suspicion. (Bloodwork abnormalities are not always present)
Failing to consider other possible causes for the observed bloodwork changes.

Utilizing Bloodwork for Monitoring Treatment Response

Once a diagnosis of FIP is made and treatment initiated, bloodwork can be valuable in monitoring the cat’s response. Improvements in anemia, white blood cell count, and A:G ratio can indicate a positive response to treatment. However, it’s important to note that bloodwork normalization may take time, and some abnormalities may persist even with successful treatment.

Conclusion: Bloodwork as a Vital Tool in FIP Management

Bloodwork is an indispensable tool in the diagnosis and management of FIP, providing valuable insights into the cat’s overall health and immune response. While it’s not a definitive diagnostic test on its own, understanding what does bloodwork look like with FIP helps veterinarians to formulate a differential diagnosis, guide further investigations, and monitor treatment efficacy, ultimately improving the chances of a positive outcome for affected cats.

Frequently Asked Questions (FAQs)

What is the significance of a low albumin to globulin (A:G) ratio in a cat’s bloodwork?

A low A:G ratio is a strong indicator of underlying inflammation or protein loss. In the context of FIP, it’s often due to decreased albumin production by the liver and increased globulin production as part of the immune response. However, other conditions, such as kidney disease, liver disease, and protein-losing enteropathy, can also cause a low A:G ratio.

Can FIP be diagnosed solely based on bloodwork?

No, FIP cannot be diagnosed solely based on bloodwork. Bloodwork findings associated with FIP are nonspecific and can be seen in other diseases. Diagnosis requires considering bloodwork results in conjunction with clinical signs, physical examination findings, and other diagnostic tests like fluid analysis, PCR, and histopathology.

What is the role of PCR testing in diagnosing FIP, and how does it relate to bloodwork?

PCR (polymerase chain reaction) testing detects the presence of the feline coronavirus (FCoV) genetic material. It can be performed on blood, fluid samples (effusions), or tissue biopsies. While a positive FCoV PCR result doesn’t definitively diagnose FIP (because FCoV is common), a high viral load and specific mutations associated with FIP can increase suspicion. Bloodwork findings, such as a low A:G ratio, can increase the likelihood of FIP and warrant PCR testing to confirm suspicion.

Are there any specific bloodwork parameters that are more indicative of wet FIP versus dry FIP?

While there’s no definitive parameter, cats with wet FIP often have more pronounced elevations in total protein and more significant fluid accumulation, which can be reflected in higher globulin levels compared to cats with dry FIP. Elevated liver enzymes might be more common in dry FIP affecting the liver.

Is it possible for a cat with FIP to have completely normal bloodwork?

Yes, it’s possible, although less common, for a cat with FIP, especially in the early stages or with atypical presentations, to have relatively normal bloodwork. In such cases, clinical signs and other diagnostic tests become even more critical for diagnosis. Serial bloodwork can also reveal changes over time.

How often should bloodwork be performed to monitor a cat undergoing FIP treatment?

The frequency of bloodwork monitoring depends on the individual cat and the treatment protocol. Initially, bloodwork might be performed weekly or bi-weekly to assess the cat’s response to treatment. As the cat stabilizes, the interval can be extended to monthly or less frequently.

What does it mean if a cat’s white blood cell count is low (leukopenia) during FIP?

Leukopenia in a cat with FIP can indicate severe immune system suppression or bone marrow involvement. It can be a negative prognostic indicator, suggesting a more aggressive form of the disease.

Can stress affect bloodwork results in cats suspected of having FIP?

Yes, stress can significantly affect certain bloodwork parameters in cats. Stress-induced hyperglycemia (elevated blood glucose) is common. Stress can also influence white blood cell counts, potentially leading to a transient increase in neutrophils. It’s important to minimize stress during blood collection whenever possible.

What other diagnostic tests are commonly performed alongside bloodwork to diagnose FIP?

Commonly performed diagnostic tests include:

Fluid analysis (if effusion is present): Analyzing the fluid’s protein content, cell count, and FCoV PCR status.
Histopathology: Examining tissue samples from affected organs under a microscope for characteristic FIP lesions.
Abdominal ultrasound: To assess organ involvement and detect fluid accumulation.
Rivalta’s test: A simple test on fluid samples to differentiate exudates (characteristic of FIP) from transudates.

How reliable is FCoV antibody testing in diagnosing FIP?

FCoV antibody testing is not reliable for diagnosing FIP. Many cats are exposed to feline coronavirus and develop antibodies without ever developing FIP. A positive antibody test simply indicates past or current exposure to FCoV, not necessarily the presence of FIP. A negative antibody test does not rule out FIP.

Can bloodwork help differentiate FIP from other diseases that cause similar clinical signs?

While bloodwork alone cannot definitively differentiate FIP from other diseases, it can narrow down the possibilities. For example, certain bloodwork patterns might be more suggestive of liver disease, kidney disease, or immune-mediated disease, prompting further investigations to rule out those conditions.

Besides the A:G ratio, what other protein abnormalities might be seen in FIP bloodwork?

In addition to a low A:G ratio, bloodwork might reveal elevated total protein levels due to increased globulins (hyperglobulinemia). Specific globulin fractions, such as gamma globulins, may be particularly elevated. Albumin levels are frequently low (hypoalbuminemia).