Ascites is a pathological (abnormal) accumulation of water in the abdominal cavity. This can be caused by many different diseases. In about 80% of all cases, the occurrence of ascites is due to parenchymal liver disease (80% of cases; essentially because of cirrhosis/damage to the liver and marked remodeling of liver tissue). In about 20 % of cases, advanced tumor disease (so-called “malignant ascites”) is present. As part of the diagnosis and treatment of the various forms of ascites, the fluid obtained by puncture is examined in laboratory tests. The following forms of ascites can be distinguished:
- Inflammatory ascites – ascites caused by inflammation.
- Non-inflammatory ascites – this includes ascites caused by tumor diseases (so-called malignant ascites).
- Hemorrhagic ascites – ascites that contains blood cells.
- Chylous ascites – accumulation of lymphatic fluid in the abdominal cavity.
The procedure
Material needed
- Ascites punctate
Preparation of the patient
- Not necessary
Disruptive factors
- Not known
Indications
- Unclear ascites
Examination of the ascites punctate including differential diagnosis
Laboratory parameters | Transsudate | Exudate |
Protein content | <30 g/l | > 30 g/l |
Specific gravity | <1.106 g/l | > 1.106 g/l |
Serum/ascites albumin quotient (SAAG). | > 1.1 (= portal-hypertensive ascites). | < 1.1 (= non-portal-hypertensive ascites) |
Differential diagnosis |
* Determination of total protein (GE) allows differentiation between cardiac (GE > 2.5 g/dl) and portal hypertensive (GE < 2.5 g/dl) genesis (origin). |
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Further examinations
- Fibronectin in ascites – differentiation between benign (“benign”) and malignant (“malignant”) ascitesValues > 75 mg/l indicate ascites of malignant originValues > 100 mg/l are found in:
- Carcinoma (possibly with liver metastases).
- CML (chronic myeloid leukemia).
- Peritoneal carcinomatosis
Levels < 75 mg/l are found in:
- Bacterial peritonitis
- Biliary cirrhosis
- Pancreatitis
Laboratory parameters for the detection of malignant ascites (modified from).
Laboratory parameters | Limit | Specificity (%) | Sensitivity (%) |
Cytology | positive | ∼ 100 | ∼ 80 |
CEA (tumor marker) | > 2.5 ng/ml | ∼ 95 | ∼ 50 |
Total protein in ascites | > 2.5 g/dl | ∼ 70 | ∼ 75 |
Cholesterol in ascites | > 45 mg/dl | ∼ 70 | ∼ 80 |
Ascites/serum LDH | > 1,0 | ∼ 70 | ∼ 60 |
Legend
- CEA = carcinoembryonic antigen.
- LDH = lactate dehydrogenase
- Sensitivity: percentage of diseased patients in whom the disease is detected by the use of the test, ie, a positive test result occurs.
- Specificity: probability that actually healthy people who do not suffer from the disease in question are also detected as healthy in the test.