|Sample Requirement||Turnaround Time|
EDTA, plain, cytospin
+/- swab for culture
Same working day (cytology)
~48 hours (culture)
Pleural fluid analysis may help with the diagnosis of pleuritis or pleuropneumonia.
To perform a pleural tap, ultrasound scan examination is recommended to confirm the presence of pleural effusion prior to tap and to locate pockets of fluid for productive sampling. Very little, if any, fluid is seen in a normal horse. The skin over the site of puncture should be clipped and prepared as for surgical intervention. A small skin incision should be made, routinely between the 6th or 7th intercostal space, 15 cm dorsal to the olecranon, or where guided by ultrasound scan for specific fluid pockets. A 7.5 cm blunt teat cannula is inserted, with a 35 ml syringe attached to prevent aspiration of air into the pleura. Pleural fluid is collected by suction.
Total nucleated cell counts >5 x 109/l suggest the presence of pleuritis. Cytological examination may reveal neoplasia, e.g. most commonly lymphoma.
Fibrinous, particulate fluid with adhesion formation is often seen in cases of pleuropneumonia).