Pleural effusion is a pathological (abnormal) increase in fluid content between the pleura parietalis (pleura) and the pleura visceralis (pleura of the lung), which can be caused by a wide variety of diseases. As part of the diagnosis and treatment of the various forms of pleural effusion, the fluid obtained by puncture is subjected to laboratory analysis. The following forms of pleural effusion can be distinguished:
- Hemorrhagic (bloody) secretion.
- Purid (purulent) secretion
- Lymph
- Exudate (see below) – more or less turbid fluid of inflammatory origin.
- Transsudate (see below) – mostly serous fluid of non-purulent origin, which is low in cells and protein.
The procedure
Material needed
- Pleural punctate
Preparation of the patient
- Not necessary
Disruptive factors
- Not known
Indications
- Unclear pleural effusion
Interpretation
Inspection (color and consistency of the punctate).
| Color and consistency | Assessment |
| Light amber and clear | normal |
| clear and viscous |
|
| pus-cloudy | Pus: pleural empyema (with foul fetid odor; massive leukocyte-rich secretion in pleural space) or abdominal abscesses |
| Milky-cloudy | A milky effusion contains fats: chylothorax:
|
| bloody | Hematothorax: |
Differentiation between exudate and transudate.
| Transudate | Exudate | |
| Total white in g/l | < 30 | > 30 |
| Specific weight | < 1.016 | > 1.016 |
| Pleural TP: serum TP (total protein quotient; total protein, TP). | < 0,5 | > 0,5 |
| LDH in U/l | < 200 | > 200 |
| Pleural LDL: serum LDL (LDL quotient). | < 0,6 | > 0,6 |
Diseases that may be associated with transudate:
- Heart failure (cardiac insufficiency): decompensated left heart failure.
- Hypalbuminemia (decreased concentration of the plasma protein albumin in blood plasma):
- Exudative enteropathy (protein-losing intestinal disease; enteral protein loss syndrome).
- Liver cirrhosis – connective tissue remodeling of the liver leading to functional impairment.
- Nephrotic syndrome – collective term for symptoms that occur in various diseases of the glomerulus (renal corpuscles); symptoms are proteinuria (excretion of protein with urine) with a protein lossof more than 1 g/m²/body surface per day; hypoproteinemia, peripheral edema due to hypalbuminemia of < 2.5 g/dl in serum, hyperlipoproteinemia (lipid metabolism disorder).
- Malnutrition
- Renal insufficiency (kidney weakness)
Diseases that may be associated with exudate:
- Bacterial infections of the thoracic or abdominal organs (e.g., tuberculosis): leukocytes ↑, glucose ↓; pathogen detection if necessary.
- Malignant neoplasms (mammary, lung and pleura: often hemorrhagic, detection of malignant cells if necessary).
- Collagenoses (group of connective tissue diseases caused by autoimmune processes) – systemic lupus erythematosus (SLE), polymyositis (PM) or dermatomyositis (DM), Sjögren’s syndrome (Sj), scleroderma (SSc) and Sharp syndrome (“mixed connective tissue disease”, MCTD).
- Pulmonary embolism
- Pneumonia (inflammation of the lungs)
- Condition n. surgery or trauma
Other laboratory parameters in unclear pleural effusion:
- Differential blood count
- Hematocrit
- PH value
- Amylase
- Glucose (blood glucose determination)
- Triglycerides
- Microbiological examination
- Cytology
| Biochemical studies |
|
| Microbiology |
|
| Cytology |
|
