Table – Abdominal Effusion (Ascites) Evaluation |
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Test |
Abnormal Result |
Interpretation and Comments |
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AFAST® and Abdominal Fluid Scoring |
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*AFAST® Negative for Free Fluid |
Abdominal Fluid Score (AFS) = 0 | *Always Repeat the Exam Post-Resuscitation and Rehydration and Continue as Part of the Physical Exam (Patient Rounds, Recheck Exams)
AFAST® Fluid Scoring Allows Tracking of Ascites
Note: Must Sample and Test Fluid when Safely Acceptable to Definitively Determine Type of Fluid because Ultrasound Cannot Reliably Characterize Free Fluid based on Echogenicity |
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*AFAST® Positive for Free Fluid |
Small Volume Effusion AFS < 3
Large Volume Effusion AFS ≥ 3 |
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Global FAST® should always be performed to stage the patient as localized versus disseminated disease (TFAST® and Vet BLUE®). |
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Biochemical Analysis |
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Hemoabdomen – Packed Cell Volume |
PCV ≥ 10-25% peripheral PCV | Must spin down sample as PCV as low as 3-5% can appear grossly like blood and in fact it’s blood contamination |
| Septic Peritonitis – Glucose | ≥ 20 mg/dL less than the venous Glucose | *Bacteria consume Glucose is a way to remember this test
Do AFAST® and fluid score and sample fluid (abdominocentesis) when safely accessible |
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Lactate |
≥ 2mmol/L greater than the venous Lactate | *Bacteria metabolically produce Lactate is a way to remember this test
Do AFAST® and fluid score and sample fluid (abdominocentesis) when safely accessible |
| Uroabdomen – Creatinine | ≥ 2:1 Peritoneal to Venous | Blood Urea Nitrogen (BUN) not used because unreliable (small molecule and to freely diffusible)
Do AFAST® and fluid score and sample fluid (abdominocentesis) when safely accessible |
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Potassium |
≥ 1.9:1 (Feline) and ≥ 1.4:1 (Canine) Peritoneal to Venous | |
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Bilioabdomen – Total Bilirubin |
≥ 2:1 Peritoneal to Venous | Cytology very helpful
Do AFAST® and fluid score and sample fluid (abdominocentesis) when safely accessible |
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Pancreatitis – Lipase |
≥ 4 times the upper reference range OR
≥ 2:1 Peritoneal to Serum |
Do AFAST® and fluid score and sample fluid (abdominocentesis) when safely accessible
Patients with Pancreatitis can get Pancreatitis-related Pleural Effusion |
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Others – Total Protein |
< 2.5 g/dL – Transudate plus low Cellularity
≥ 2.5 – 5.0 g/dL – Modified Transudate plus low Cellularity > 3.0 g/dL – Exudate (Non-septic, Septic) plus high Cellularity > 3.0 g/dL – Hemorrhagic > 2.5 g/dL – Neoplastic |
Transudate – Pre-hepatic Portal Hypertension (lymph from weeping small intestine), Liver Disease, Low Albumin (< 1.6 g/dl), Vasculitis
Do Global FAST® for any obvious soft tissue abnormalities. Modified Transudate – Post-hepatic Portal Hypertension (lymph from weeping liver [or less commonly spleen]), Liver Disease, *Right-sided Congestive Heart Failure, Splenic Torsion, Liver Lobe Torsion Do Global FAST® for TFAST® echocardiography views and AFAST®-TFAST® Diaphragmatico-Hepatic View for a distended caudal vena cava and hepatic veins Do Global FAST® for any masses, evidence of co-morbidities, that could provide additional helpful information Do Global FAST® for any masses, evidence of co-morbidities, that could provide additional helpful information Do Global FAST® for any masses, evidence of co-morbidities, determining if localized versus disseminated disease (Global FAST® Staging) that could provide additional helpful information including possible locations for tissue biopsy |
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Microscopic Evaluation |
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Predominant Cell Type |
Neutrophils
Lymphoblasts Red Blood Cells Small Mature Lymphocytes Sheets of Cells of ≥ 8-16 cells |
Consider Inflammatory disease, Non-septic and Septic (when degenerate, engulfed bacteria, fungal organisms), Chronic hemorrhage when engulfed red blood cells)
Consider Lymphoma Consider Blood Contamination versus True Hemorrhage (run comparative PCVs) Consider Chylous (high Triglycerides) and Pseudo-chylous effusion (high Cholesterol and protein-lecithin compounds), both grossly milky white to milky pinkish appearance. Rule of thumb – Chylous is more common and does NOT clear with centrifugation Consider Carcinoma/Neoplasia |
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Bile Pigment |
Gold, green, black-brown, free or engulfed in neutrophils, macrophages | Consider Bile peritonitis |
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Intracellular Organisms |
Intracellular bacteria, fungal organisms
Extracellular bacteria, fungal organisms |
Consider Septic (bacterial, fungal) peritonitis
Consider (bacterial, fungal) contamination from bowel aspirate |
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*Total Nucleated Cell Count |
Mononuclear <1,000/ul – Transudate
Mononuclear 1,000-8,000/ul – Modified Transudate Neutrophils >3,000/ul – Non-septic Exudate Neutrophils >3,000/ul – Septic Exudate Similar to Blood with Variable Counts – Hemorrhagic Tumor Cells with Variable Counts – Neoplasia |
*Combine findings of Cytology with Biochemical analysis |
| *Cytology has been estimated to vary between 60-80% sensitive for the presence of bacterial septic peritonitis, combine with Glucose and Lactate testing. | ||
| References:
Alleman AR, Abdominal, thoracic, and pericardial effusions. The Veterinary Clinics Small Animal Practice 33(2003): 89-118. |
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Created by Dr. Gregory Lisciandro, DVM, Dipl. ABVP, Dipl. ACVECC of FASTVet.com Copyright 2021 |
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