Peer-reviewed veterinary case report
How to Tell Different Types of Fluid in Cats' Chest Accurately
By Mazzei, A et al.·Published in Veterinary clinical pathology·2025·San Marco Veterinary Clinic and Laboratory, Italy·View original on PubMed →
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Original publication title: Comparative Diagnostic Accuracy of Pleural Effusion Classification Methods in Cats: An Analysis of Naturally Occurring Cases.
- Species:
- cat
Plain-English summary
A group of 83 cats with fluid in their chest (pleural effusion) was studied to see how well different methods could identify the cause of the fluid. The cats had either exudates (fluid from inflammation) or transudates (fluid from pressure changes), with 55 having exudates and 28 having transudates. The simplified Light's criteria method was found to be very accurate, correctly identifying most cases, while traditional veterinary methods were less reliable. This means that using the simplified Light's criteria could help vets diagnose the cause of pleural effusion more effectively, leading to better treatment options for affected cats.
People also search for: cat pleural effusion treatment · cat fluid in chest causes · how to diagnose cat chest fluid
Abstract
BACKGROUND: Pleural effusion (PE) in cats can result from transudative or exudative processes. Transudates are caused by decreased colloid osmotic pressure (↓COP) or elevated hydrostatic pressure (↑HP) gradient, while exudates arise from increased pleural capillary permeability. Diagnostic classification approaches traditionally rely on pleural effusion total protein (TP) and total nucleated cell counts (TNCC). In contrast, Light's criteria employing pleural effusion lactate dehydrogenase (LDH), LDHdivided by serum LDH (LDH), and pleural effusion to serum protein ratio (TP) are more accurate than classification based on TP/TNCCin humans and show promise in cats. OBJECTIVES: To assess the diagnostic accuracy of TNCC, LDH, LDH, TP, and TPin classifying feline PEs in ↑HP-transudates, ↓COP-transudates, or exudates and to compare simplified Light's criteria (which relies solely on LDH) with Light's criteria and existing veterinary classification schemes based on TPand TNCC(named Vet-A and Vet-B). METHODS: Cross-sectional study including 83 client-owned cats with PE. RESULTS: There were 55 exudates, 28 ↑HP-transudates, and 0 ↓COP-transudates. All the variables analyzed were significantly different between exudates and transudates. Simplified Light's criteria correctly classified 50/55 exudates and 26/28 ↑HP-transudates (sensitivity = 91%, specificity = 93%, accuracy = 92%). Light's criteria correctly identified 55/55 exudates but misclassified 15/28 ↑HP-transudates as exudates (accuracy = 82%). Traditional veterinary schemes showed lower accuracies: Vet-A (57%) and Vet-B (74%). Simplified Light's criteria outperformed Vet-A (p < 0.001) and Vet-B (p = 0.007) and trended higher than Light's criteria (p = 0.096). CONCLUSIONS: Simplified Light's criteria demonstrate excellent diagnostic accuracy, outperforming traditional veterinary classification schemes.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41058604/