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![Distinguishing Transudates From Exudates
The Light's Criteria -measures serum and pleural fluid protein and LDH
15
Pleural fluid protein/serum protein ratio greater than 0.5, or
Pleural fluid LDH/serum LDH ratio greater than 0.6, or
Pleural fluid LDH greater than two-thirds the upper limits of the
laboratory's normal serum LDH
Light's criteria yield a 97.5% sensitivity and 80% specificity.
[Reappraisal of the standard method (Light's criteria) for identifying pleural exudates]. 2006,José M Porcel et al](https://image.slidesharecdn.com/pleuralfluidanalysis-241025125556-3c4accf6/85/Pleural-fluid-analysis-Approach-Body-fluid-analysis-15-320.jpg)
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Pleural fluid analysis - Approach (Body fluid analysis)
The document discusses pleural effusion, a pathological accumulation of fluid in the pleural space often resulting from cardiovascular or inflammatory conditions. It outlines the clinical presentation, necessary workups including thoracentesis, and differentiates between transudative and exudative effusions based on specific criteria. The document emphasizes the importance of biochemical and cytological analysis to determine the underlying causes of pleural effusions.
Pleural fluid analysis - Approach (Body fluid analysis)
- 1. Prepared : DrJackson Facilitator: Dr Benson Body Fluid Analysis Tasakhtaa Hospital
- 2. Body fluids ofclinical importance Pleural Effusion Anatomy Clinical presentation Physical findings 01 02 03 04 05 Contents 02 WorkUps Analysis 06 07
- 3. CSF Pleural Pericardial Ascitic Body fluids ofclinical Importance 03
- 4. Pleural Effusion Pleural effusionis collection of fluid abnormally present in the pleural space, usually resulting from excess fluid production and/or decreased lymphatic absorption. 04 Etiologies range in spectrum from cardiopulmonary disorders and/or systemic inflammatory conditions to malignancy.
- 5. Anatomy Altered permeability –pleural membranes/ capillaries Decrease of intravascular oncotic pressure Increase of capillary hydrostatic pressure – pulmonary/ systemic circulation Decreased lymphatic drainage or complete lymphatic vessel blockage Extravasation of peritoneal fluids across diaphragm Imbalance between hydrostatic and oncotic forces in the visceral and parietal pleural capillaries and persistent sulcal lymphatic drainage. 05 Mechanisms playing role in formation of pleural effusion
- 6. Clinical Presentation Clinical presentationvaries with the underlying cause Pulmonary symptoms Commonly a/w •dyspnea, cough and pleuretic chest pain 06 Extra-pulmonary symptoms Lower limb edema Orthopnea PND Night sweats Fever Hemoptysis Weight loss
- 7. Physical Findings Dullness topercussion Decreased tactile fremitus Asymmetrical chest expansion Mediastinal shift away from the effusion Diminished or inaudible breath sounds Pleural friction rub Physical findings are seen observed when PF >300mls. Other physical and extrapulmonary findings may suggest the underlying cause of the pleural effusion. 07
- 8. WorkUps 08 Before analyzing Pleuraleffusion , Pleural tapping or thoracentesis should be performed. Thoracentesis is percutaneous (sterile) procedure where pleural fluid is removed through a needle or a catheter. Usually performed at bedside. It's diagnostic- (nature & cause) therapeutic – relieve dyspnea Contraindicated – active skin infections, open wound infection, bleeding disorders
- 9. Sample collection Specimens shouldbe collected in tubes containing anticoagulants EDTA (puple top) Heparin (green top) Between 20 to 40 mL of pleural fluid is needed for a complete analysis biochemical cytological microbiology studies 09 A total volume of 3–5 mL is enough for the sequential measurement
- 10. Normal PF characteristics 10 Clearultrafiltrate of plasma A pH of 7.60-7.64 Protein content of less than 2% (10-20 g/L) Fewer than 1000 white blood cells (WBCs) per cubic millimeter Glucose content similar to that of plasma Lactate dehydrogenase (LDH) less than 50% of plasma
- 11. Color Ddx Frankly Purulent Amilky, opalescent fluid Grossly bloody fluid Black pleural fluid Appearance 11 Empyema Chlyothorax Trauma, malignancy, postpericardiotomy syndrome, or asbestos-related effusion Infection with Aspergillus niger , malignant melanoma,
- 12. Analysis 12 Second step isevaluating if the fluid is Transudate or Exudative. Transudates - Imbalance in oncotic and hydrostatic pressures. Exudates- Inflammatory processes of the pleura and/or decreased lymphatic drainage.
- 13. Exudative causes Transudativecauses Infectious causes ie. TB, pneumonia Maligancy Parapneumonic causes Pulmonary embolism Collagen-vascular conditions - RA, SLE Pancreatitis Trauma Meigs syndrome Post CABG Chylothorax 13 Congestive heart failure Cirrhosis Pulmonary embolism Atelectasis Hypoalbuminemia Nephrotic syndrome Peritoneal dialysis
- 14. 14 If Exudative More diagnostictests are required in order to determine the cause of the local disease If Transudative Establish or rule out a diagnosis of congestive heart failure, cirrhosis, or pulmonary embolism or other causes Initial measurement should be limited to the PF protein and LDH levels.
- 15. Distinguishing Transudates FromExudates The Light's Criteria -measures serum and pleural fluid protein and LDH 15 Pleural fluid protein/serum protein ratio greater than 0.5, or Pleural fluid LDH/serum LDH ratio greater than 0.6, or Pleural fluid LDH greater than two-thirds the upper limits of the laboratory's normal serum LDH Light's criteria yield a 97.5% sensitivity and 80% specificity. [Reappraisal of the standard method (Light's criteria) for identifying pleural exudates]. 2006,José M Porcel et al
- 16. The Light's Criteria-misclassify approximately 20-25% of transudates as exudates, 16 Long-term use diuretic therapy for CHF Serum minus pleural protein concentration level < 3.1 g/dL A gradient of serum albumin to pleural fluid albumin < 1.2 g/dL Because of the concentrating effect of diuresis on protein and LDH levels within the pleural space Counteract
- 17. Evaluation of exudativeeffusion 17 Total and differential cell counts Smears and cultures for organisms Glucose and LDH levels Cytologic analysis Pleural-fluid marker of tuberculosis – ADA>35u/l
- 18. Cell differentials 18 A highlymphocyte count (>50%) TB, Malignancy, chronic rheumatoid pleurisy, Lymphoma, Renal/liver failure A predominance of neutrophils( >50%) Parapneumonic effusions, PE, Pancreatitis, A predominance of mononuclear cells Chronic process. Pleural-fluid eosinophilia (>10%) Pneumothorax, Hemothorax, Drugs, Tuberculosis pleurisy, Malignancy
- 19. Smears and Cultures 19 Aerobicand anaerobic bacteria Pleural effusion Protein Transudates < 30g/l TB >40g/l Waldenström’smacroglobulinemia and multiple myeloma70-80g/l
- 20. Pleural fluid LDH 20 >1000IU/L – empyema, rheumatoid pleurisy, malignancy Elevated in Pneumocystis jiroveci PF:Serum LDH >1. PF/Serum protein<1 Pleural effusion Glucose Low PF glucose (1.7-2.8mmol/l) - malignant effusion, tuberculouspleuritis, esophageal rupture, or lupus pleuritis. Very low levels of PF glucose (<1..7 mmol/l)- rheumatoid pleurisy or empyema
- 21. Cytology 21 Establish the diagnosisof malignant pleural effusions ADA Distinguish between malignant and tuberculous pleurisy when an exudative effusion is lymphocytic > 35 to 50 U/L - tuberculous pleural effusions > 40 U/L- diagnostic threshold used to establish tuberculous pleural
- 22. References Pleural Effusion -Medscape 1. Diagnostic evaluation of pleural fluid- UpToDate 2. Pleural Effusion: Clinical practise Richard W LIght, M.D. 3. HANDLING PLEURAL FLUID SAMPLES FOR ROUTINE ANALYSES, José M. Porcel 4.