Peritoneal fluid is a serous fluid made by the

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesot ...

in the

abdominal cavity The abdominal cavity is a large body cavity in humans and many other animals that contains many organs. It is a part of the abdominopelvic cavity. It is located below the thoracic cavity, and above the pelvic cavity. Its dome-shaped roof is th ...

which

lubricate Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubrica ...

s the surface of tissue that lines the

abdominal wall In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls. There is a common set of layers covering and forming all the walls: the deepest being the v ...

and

pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reprod ...

. It covers most of the organs in the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the tors ...

. An increased volume of peritoneal fluid is called

ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, a ...

. Sampling of peritoneal fluid is generally performed by paracentesis.

Peritoneal fluid analysis

The serum-ascites albumin gradient (SAAG) is the most useful index for evaluating peritoneal fluid and can help distinguish ascites caused by portal hypertension (cirrhosis, portal vein thrombosis, Budd-Chiari syndrome, etc.) from other causes of ascites. SAAG is calculated by subtracting the albumin measure of ascitic fluid from the serum value. In portal hypertension, the SAAG is >1.1 g/dL while ascites from other causes shows a SAAG of less than 1.1 g/dL. Peritoneal fluid microscopy is a useful test in evaluating the cause of ascites. A diagnostic peritoneal lavage (DPL) is considered positive if any of the following are present De Mais, Daniel. ASCP Quick Compendium of Clinical Pathology, 2nd Ed. ASCP Press, Chicago, 2009. # >15 mL gross blood # RBCs >100,000/mL # WBCs >500/mL # Bacteria present on

Gram stain In microbiology and bacteriology, Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish ba ...

Bacteria and white blood cells, when present in a patient with a history of ascites (usually due to

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

) is highly suggestive of spontaneous bacterial peritonitis.

References

External links

Peritoneal fluid
entry in the public domain NCI Dictionary of Cancer Terms Body fluids {{digestive-stub