Felis ISSN 2398-2950 Pleural fluid: analysis Contributor(s): Yvonne McGrotty Overview Sampling Tests Result Data Overview The pleural cavity normally contains only a small amount of fluid; little or no fluid can be obtained by aspiration unless excess fluid (pleural effusion Pleural effusion) is present. Gross appearance of the fluid can provide information which may assist in determining the nature of the fluid, eg a milky solution may be chylous. Investigation of effusions commonly includes some or all of the following: Cell counts Pleural fluid: differential cell count. Refractometry for total protein Pleural fluid: protein. Cytology Pleural fluid: cytology. Culture Pleural fluid: culture and sensitivity. Additional biochemical analyses may be of benefit for further characterization. Aim to classify effusion initially into: Transudate. Modified transudate. Exudate. Sampling This article is available in full to registered subscribers Sign up now to purchase a 30 day trial, or Login Tests MethodologiesPhysical character Color. Turbidity. Coagulation. Odour. If the effusion is hemorrhagic, PCV Hematology: packed cell volume should be performed on the fluid. Biochemistry To determine: Protein content Pleural fluid: protein. Presence of lipids (triglycerides and cholesterol). Cytology Pleural fluid: cytology. Cell count and differential Pleural fluid: differential cell count. Culture and sensitivity Pleural fluid: culture and sensitivity. Availability Readily available. Technique (intrinsic) limitations Does not always reveal underlying cause of effusion. Technician (extrinsic) limitations Cytological interpretation may be difficult, especially in differentiating neoplasia from reactive mesothelial cells - send for expert analysis. Result Data This article is available in full to registered subscribers Sign up now to purchase a 30 day trial, or Login Further ReadingPublicationsRefereed papers Recent references from VetMed Resource and PubMed. Tyler R D et al (1989) Evaluation of pleural and peritoneal effusions. Vet Clin North Am Small Anim Pract 19(4), 743-768.