Reference values for equine peritoneal fluid

Abstract

Twenty horses, aged 1-17 yr (mean age 6 yr), presented for elective destruction and subsequently found at autopsy to have no significant peritoneal alterations, were used to determine a variety of reference values for peritoneal fluid. [Abdominal disorders in the horse occur frequently and differential diagnosis is often difficult. The use of peritoneal fluid as an aid to diagnosis is described.] Samples were collected ante mortem or within 1 h post mortem. Each cavity contained 100-300 ml of usually clear, pale yellow fluid which in a clinical refractometer showed a mean specific gravity 1.010 and mean (.+-. SD) total protein 7.7 .+-. 3.6 g/l. The mean total nucleated cell count and, proportionally, polymorphonuclear leukocytes averaged 45.2%, mononuclear phagocytes 47%, lymphocytes 7.8%, eosinophils 0.7% and basophils and mast cells zero. Eosinophils were not usually seen but 6 samples had 1-5%. The peritoneal fluid chemical profile (mean .+-. SD) was: aspartate aminotransferase (AST) 118.9 .+-. 46.9 N/l; alkaline phosphatase (AP) 56.0 .+-. 52.7 IU/l; lactate dehydrogenase (LDH) 143.0 .+-. 106.1 IU/l; total bilirubin (TB) 8.0 .+-. 6.2 .mu.mol/l; total protein (TP) (biuret method) 14.2 .+-. 6.8 g/l; urea N (BUN) 6.1 .+-. 1.1 mmol/l; glucose 7.7 .+-. 1.8 mmol/l; inorganic phosphate (IP) 1.4 .+-. 0.5 mmol/l; Ca 2.0 .+-. 0.2 mmol/l. TP, BUN, closely correlated with levels in paired serum samples.