[Usefulness of lactate dehydrogenase concentration in thoracic and abdominal fluid of dogs]

The aims of this study were to investigate the usefulness of LDH measurement in effusions in dogs to classify the fluid as exudate or transudate and to classify the fluid based on the pathophysiological mechanism. In thoracic (n = 107) and abdominal (n = 199) fluid of dogs cell count, protein and LDH concentrations were measured. The fluid was retrospectively categorized into exudate (group A), protein-poor (B) or protein-rich transudate (C) as well as based on pathophysiology into the following five groups (group 1 - 5): hemorrhagic, chylous, inflammatory, oncotic and congestive. In thoracic and abdominal fluid LDH concentrations were significantly higher in group A compared to group B and C. There was a significant difference of LDH concentration between the groups 1 to 5 in both thoracic and abdominal fluid, however there was a large overlap between the five groups. While fluid LDH measurement in dogs is helpful to distinguish exudate from transudate it is only of little help to elucidate the pathophysiological cause.