Examination of an Ascites Punctate

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
  • Hypalbuminous ascites:
    • Malnutrition
    • Hypalbuminemia (decreased albumin (protein) concentration in the blood).
    • Hypothyroidism (underactive thyroid gland)
    • Nephrotic syndrome
  • Cardiac (“heart-related”) ascites* :
    • Heart failure (cardiac insufficiency).
    • Valvular heart disease,
    • Constrictive pericarditis (“armored heart“).
  • Portal ascites* :
    • Liver cirrhosis
    • Budd-Chiari syndrome (thrombotic occlusion of the hepatic veins),
    • Pford vein thrombosis

* Determination of total protein (GE) allows differentiation between cardiac (GE > 2.5 g/dl) and portal hypertensive (GE < 2.5 g/dl) genesis (origin).

  • Inflammatory ascites: Leukocytes ↑ (pyogenic peritonitis/superficial peritonitis; > 250 granulocytes/mm3 define spontaneous bacterial peritonitis, SBP); if infected ascites is suspected, microbiological culturing to detect the causative agent (e.g., tuberculous peritonitis; spontaneous bacterial peritonitis (SBP): mainly gram-negative bacteria, for example, E. coli).
  • Malignant (“malignant”) ascites:
    • CUP syndrome: Cancer of Unknown Primary (engl. ): cancer with unknown primary tumor (in about 20% of cases with malignant ascites/malignant ascites the primary tumor remains unknown).
    • Bronchial carcinoma (lung cancer).
    • Endometrial carcinoma(cancer of the uterus)
    • Gastrointestinal tumors (gastrointestinal tumors).
    • Hepatocellular carcinoma (HCC; hepatocellular carcinoma/liver cell cancer).
    • Colon carcinoma (colon cancer)
    • Liver metastases
    • Malignant lymphoma (malignant neoplasm originating from lymphoid cells).
    • Gastric carcinoma
    • Mammary carcinoma (breast cancer)
    • Ovarian carcinoma (ovarian cancer)
    • Pancreatic carcinoma (pancreatic cancer)
    • Peritoneal carcinomatosis – diffuse metastases (daughter tumors) in the peritoneum (peritoneum).
    • Pseudomyxoma peritonei (biliary abdomen)[amylase and lipase ↑]

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:

    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.