Special Precautions/Comments:

Interferences: Detection of organisms may be impacted if the patient has taken antibiotics prior to the sample being taken.

Clotted or blood-stained samples will interfere with the cell count result.

Method: The investigation of ascitic fluid samples involves a white blood cell count, examination of a Gram stained smear and culture for pathogens. Any organisms isolated are identified using Maldi-Tof and antimicrobial susceptibility testing is performed on significant isolates. Calibration: Equipment calibrated to UKAS standard. EQA scheme: UKNEQAS General Bacteriology scheme (culture and identification). BMS MICRO Sterile FLUID EQA (cell counts). IQC: In-house preparations (gram stains).

Interpretation: A white cell count below 250 x 10*6/L  is regarded as Negative (within normal range). A white cell count above  250 x 10*6/L will be reported as Positive. All positive results will be reviewed by the Consultant Microbiologist.

A negative culture will be reported as No organisms isolated. A positive culture will be reported as Organisms isolated and significant organisms will be identified.  Positive cultures will be followed with sensitivity testing on significant organisms.

 

Additional Information:

Background information: Peritonitis is inflammation of the peritoneum, the serous membrane lining the abdominal cavity and covering the abdominal viscera. Primary bacterial peritonitis accounts for <1% of bacterial peritonitis and occurs spontaneously without evidence of intra-abdominal organ perforation. It is most frequently seen in children and particularly those with nephrotic syndrome.

Spontaneous bacterial peritonitis (SBP) is the infection of pre-existing ascites in the absence of known intra-abdominal infection, and is a frequent, serious complication of cirrhosis and other liver disease. Infection is almost always mono-microbial, usually resulting from haematogenous spread.

Secondary bacterial peritonitis usually arises following gastrointestinal leakage within the peritoneal cavity. This leakage may follow perforation of diseased viscera or abdominal trauma. The commonest cause in western countries is acute appendicitis. Other causes include perforated peptic ulcer, diverticular disease of the colon, pancreatitis and cholecystitis and as a complication of CAPD.

Localised peritonitis develops over any inflamed area of the gastrointestinal tract. It is a milder condition that may resolve, but may leave residual adhesions.

Acute generalised peritonitis is an extremely serious and often fatal condition. It usually arises as a consequence of leakage of gastrointestinal tract contents from a perforated ulcer or from a ruptured gangrenous appendix. The large quantity of bacterial toxins absorbed often leads to the development of paralytic ileus, toxaemia and septic shock.

Keywords: Ascites, ascitic fluid, peritonitis