SEROUS FLUID
Serum-like fluid found bet membranes
Ultrafiltrate of plasma
2 membranes - parietal (lines cavity wall)
- visceral (covers the organs)
Production and reabsorption - constant rate
FORMATION
Effusion - ↑ fluid between membranes
Pathologic causes of Effusion
Increased capillary hydrostatic
pressure
Congestive heart failure
Salt and fluid retention
Decreased oncotic pressure
Nephrotic syndrome
Hepatic cirrhosis
Malnutrition
Protein-losing enteropathy
Increased capillary permeability
Microbial infections
Membrane inflammations
Malignancy
Lymphatic obstruction
Malignant tumors, lymphomas
Infection and inflammation
Thoracic duct injury
Transudate Exudate
Appearance Clear Cloudy
Fluid:serum protein ratio <0.5 >0.5
Fluid:serum LD ratio <0.6 >0.6
WBC count <1000/uL >1000/uL
Spontaneous clotting No Yes
Pleural fluid cholesterol <45-60 mg/dL >45-60 mg/dL
Pleural fluid: serum cholesterol <0.3 >0.3
Pleural fluid: bilirubin ratio <0.6 >0.6
Serum-Ascites Albumin Gradient >1.1 <1.1
SPECIMEN COLLECTION AND HANDLING
Thoracentesis - pleural fluid
Pericadiocentesis - pericardial fluid
Paracentesis - peritoneal fluid
>100 - usually collected
Tubes Purpose
EDTA Cell count
Heparinized/Clotted Blood Chemistry
Sterile heparinized/SPS Microbiology, Cytology
Anaerobically on ice Specimen for pH
TRANSPORT AND STORAGE
Maintained at RT & transported ASAP
Refrigated - for cytology
LABORATORY TESTS
Gross/Physical: appearance, volume, spontaneous clotting Cell
count and differential count
Chemistry: protein, cholesterol, LD, fluid-to-blood ratios
Microbiology: GS, CS, AFS, fungal stain
Cytology
PLEURAL FLUID
Appearance
Normal - Clear, pale yellow
Appearance Disorder
Turbid/
White
Microbial infection (tuberculosis)
Bloody Hemothorax Hemorrhagic effusion, pulmonary
embolus, tuberculosis, malignancy
Milky Chylous material from thoracic duct
leakage
Pseudochylous material from chronic
inflammation
Brown Rupture of amoebic liver abscess
Black Aspergillus
Viscous Malignant mesothelioma (increased
hyaluronic acid)
Significance of Cells Seen in Pleural Fluid
CELLS ASSOCIATED CONDITIONS
Neutrophils Pneumonia, pancreatitis,
pulmonary infarction
Lymphocytes TB, viral infection, autoimmune
disorders, malignancy
Mesothelial Cells Normal and reactive forms have
no clin sig, decreased in TB
Plasma Cells TB
Malignant Cells 10 adenocarcinoma and small-cell
carcinoma, metastatic carcinoma
ANALYTE ASSOCIATED CONDITIONS
Glucose Decreased in rheumatoid inflammation and
purulent infection
Lactate Increased in bacterial infection
Triglycerides Increased in chylous infection
Amylase Increased in pancreatitis, esophageal rupture,
malignancy
pH Decreased in unresponsive pneumonia and
esophageal rupture
PERICARDIAL FLUID
Result of changes in the membrane permeability due to
infection (pericarditis), malignancy, and trauma-producing
exudates.
By metabolic disorders such as uremia, hypothyroidism, and
autoimmune disorders are the primary causes of transudates.
Normal volume: 10-50 mL
APPEARANCE
Chylous Effusion Pseudochylous
Effusion
Cause Thoracic duct leakage Chronic inflammation
Appearance Milky/white Milky/green
Leukocytes Lymphocyte predominant Mixed cells
Sudan III stain Yes No
Cholesterol Absent Present
Triglycerides > 110 mg/dL < 50 mg/dL
Ether solubility Extractable Not extractable
