Table 26-2.

Cytological analysis of peritoneal fluid48, 62, 63

	Levels	Does the cat have peritonitis?
Nucleated cell count	>13,000 cells/µL	100% sensitivity and specificity*
Glucose concentration	<20 mg/dL or more lower than peripheral blood glucose	86% sensitive, 100% specific*
Peripheral venous blood lactate	1.3–10.6 mmol/L (median = 6.2 mmol/L)	Affected cats
1.2–1.6 mmol/L (median = 1.4 mmol/L)	Unaffected cats
Bile crystals	Presence of intra- and extracellular bile crystals	Bile peritonitis
Bilirubin	Two to three times higher than peripheral blood levels	Bile peritonitis
Creatinine	Increased levels compared to serum. Mean abdominal fluid creatinine-to-serum creatinine ratio = 2 : 1 (range, 1.1 : 1 to 4.1 : 1)	Uroperitoneum
Potassium	Increased levels compared to serum. Mean abdominal fluid K+ to serum K+ ratio was 1.9 : 1 (range, 1.2 : 1 to 2.4 : 1)	Uroperitoneum

^*, for diagnosing peritonitis.