Finding the right tests…
Emergency services available 24 x 7
Emergency services available 24 x 7
Finding the right tests…
Microbiology
Fluid that collects in your abdomen from liver disease, called ascites, is not supposed to carry bacteria, so when it does, doctors treat it as an emergency called spontaneous bacterial peritonitis. This infection can develop without any obvious source, so a fluid culture is sent in anyone hospitalised with new or worsening ascites. The best yield comes from injecting fluid directly into blood culture bottles at the bedside rather than a plain sterile container, since this improves the chance the organism actually grows. Even with good technique, the organism isn't identified in every true case, which is why the same tap is also checked for white blood cell counts, and antibiotics often start on that count alone.
A positive culture names the bacteria growing in your abdominal fluid, most often a gut organism such as E. coli or Klebsiella, and lists which antibiotics work against it. A negative result does not rule out infection on its own, since the causative organism goes unidentified in a real share of confirmed cases, particularly if antibiotics were already started. That is why the ascitic fluid white blood cell count, checked from the same sample, is used as the main trigger for starting treatment, with culture confirming and refining it afterward.
The fluid inside your abdomen is meant to be free of bacteria, so a positive culture from a properly collected sample points to a real infection, unlike a stool or skin sample where some bacteria are expected. In people with cirrhosis, this infection, called spontaneous bacterial peritonitis, can develop with no clear entry point and can turn serious quickly.
Ascitic fluid often carries a low number of bacteria, so a plain sterile container can under-detect them. Inoculating the fluid directly into blood culture bottles at the bedside, the same bottles used for a blood culture, is preferred by many centres because it raises the chance the organism actually grows in the lab.
Even with good bedside technique, the responsible organism cannot be identified in a real share of cases that are clinically confirmed as spontaneous bacterial peritonitis by other means. Because of this gap, the same fluid sample is also sent for a white blood cell count, and a raised count is treated as enough evidence to start antibiotics right away, without waiting on the culture.
Most confirmed cases grow gut bacteria, particularly E. coli and Klebsiella species, reflecting how these infections usually start - bacteria crossing from the gut into fluid that has no defence against them.
In people with cirrhosis and ascites, bacteria can cross from the gut into the abdominal fluid without any wound or obvious entry point. Because this infection, spontaneous bacterial peritonitis, can turn serious quickly, doctors send a culture in anyone with new or worsening ascites rather than waiting for a specific sign.
Ascitic fluid often carries a smaller number of bacteria than blood, so plain containers can miss them. Putting the fluid directly into blood culture bottles at the bedside improves the odds of the organism actually growing in the lab.
A negative culture doesn't rule out infection, since the organism goes unidentified in a real share of confirmed cases. Your doctor also relies on the white blood cell count from the same tap, and treats a raised count as reason enough to start antibiotics.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
It's an infection of the fluid that collects in the abdomen in people with liver disease, occurring without any wound, surgery, or other clear source. It's considered a medical emergency because it can worsen quickly if untreated.
Often yes. Since spontaneous bacterial peritonitis can progress fast and the culture result takes time, antibiotics are frequently started based on the fluid's white blood cell count and then adjusted once the culture and sensitivity results are available.
A routine ascitic fluid test looks at things like protein, albumin, and cell counts, which can appear abnormal within hours. Culture instead waits to see whether a living organism actually grows, which gives a specific answer about what's causing the infection, if there is one.