Synonym
Tubes
40-50 mL of ascitic fluid, typically collected in 4 tubes (10 mL in each)
- Lavender top tube for cell count and differential
- Sterile tube/blood culture bottle for microbiological studies, Gram stain, and Ziehl-Nielsen staining
- Red or green top tube for chemistry
- Sterile tube for cytology
Additional information
- Aspiration is done very cautiously in pregnant women, in patients with bleeding tendencies, and unstable vital signs
- Consider blood draw for other additional appropriate studies such as albumin, LDH, PT and any other indicated studies
- Instruct the patient to void urine just before test
- Monitor vital signs, and observe for dizziness, pallor, perspiration, and increased anxiety during procedure
- Send sample to lab immediately
Ascitic fluid aspiration procedure (diagnostic paracentesis)
- Consent patient for procedure and have them empty their bladder
- Patient lies on his/her back, tilting toward one side
- Ultrasonic guidance is commonly used to locate an appropriate site for aspiratio
- Sterilize the skin with chlorhexidine or betadine and use sterile technique thereafter
- Local anesthetic, such as 1% lidocaine (2-3 mL), is infiltrated with a small gauge needle, at and below the site where shifting dullness is detected
- Aspirate ascitic fluid using an appropriate needle (18-20 ga) or kit designed for aspiration, with a 50 mL syringe
- In a 4-quadrant tap, fluid is aspirated from each quadrant of the abdomen
- Rare complications include bowel perforation, secondary bacterial peritonitis, or hemorrhage
Info
- Ascitic fluid analysis (cell count/culture) is performed to detect and estimate the presence and type of cells and pathological microorganisms in the ascitic fluid
- The peritoneal cavity and organs within the abdomen are lined with a protective membrane. Normally only a small amount of serous fluid is present in the cavity as the rates of fluid production and absorption are equal
- Ascitic fluid is the pathologic accumulation of fluid in the peritoneal spaces, which may be transudate or exudate (more rarely from thoracic duct leak with chylous ascites, post surgical with bile duct injury)
- Transudates are effusions that form as a result of a systemic disorder that disrupts the regulation of fluid balance, as in congestive heart failure, cirrhosis of the liver, or hypoalbuminemia
- Exudates are caused by conditions involving the tissue of the membrane itself, as in infection or malignancy which can result in secretion of excessive ascitic fluid
Clinical
- The clinical utility of ascitic fluid analysis for cell count and culture includes
- To evaluate and determine the cause of ascites
- To investigate peritoneal rupture or perforation
- To determine suspected cirrhosis, peritoneal carcinomatosis, or infection (tuberculous peritonitis)
- To distinguish spontaneous from non-perforation secondary bacterial peritonitis, usually by ascitic fluid PMN count in response to antibiotic therapy
- Small amounts of ascites are usually asymptomatic
- Larger amounts of ascites may clinically present as:
- Abdominal distention and discomfort
- Anasarca (suggestive of cardiac disease or nephrotic syndrome)
- Anorexia
- Early satiety
- Elevated jugular venous pressure (suggestive of cardiac origin)
- Gastroesophageal reflux
- Flank pain
- Nausea
- Puddle sign
- Respiratory distress
- Shifting dullness on percussion
- Umbilicus may be everted
- Findings suggestive of liver disease, such as jaundice, palmar erythema, and spider angiomas
- Spontaneous bacterial peritonitis (SBP) in adults is usually due to enteric organisms, mainly gram-negative bacilli, and may clinically present with:
- Acidosis
- Fever and chills
- Gastrointestinal bleeding
- Generalized abdominal pain
- Sepsis
- Shock
- Worsening encephalopathy
- Worsening renal function
- The differentiating features of secondary bacterial peritonitis and spontaneous bacterial peritonitis, includes:
| Secondary
bacterial
peritonitis | Spontaneous
bacterial
peritonitis |
|---|
| Organisms | Multiple | Single |
| Ascitic protein | >1 g/dL | <1 g/dL |
| Response to treatment |
| PMN count | Continues to rise
despite treatment | Falls exponentially |
| Ascitic culture | Remains positive | Rapidly becomes
sterile |
Overview on appearance
- Cloudy or turbid ascitic fluid is suggestive of peritonitis due to conditions, which include:
- Appendicitis
- Pancreatitis
- Primary bacterial infection
- Ruptured bowel
- Strangulated or infarcted intestine
- Bloody ascitic fluid may result from conditions, which include:
- Abdominal trauma
- Benign or malignant tumor
- Hemorrhagic pancreatitis
- Traumatic tap
- In traumatic aspiration, initially bloody fluid becomes clear on continued aspiration
- Milk-colored peritoneal fluid may result from chyle or lymph fluid escaping from thoracic duct that is damaged or blocked in conditions such as:
- Adhesions
- Hepatic cirrhosis
- Lymphoma
- Malignant tumor
- Parasitic infestation
- Tuberculosis
- Pseudochylous condition may result from presence of leukocytes or tumor cells and can be differentiated from true chylous ascites that is characterized by elevated triglyceride levels and microscopic fat globules
- Bile-stained green ascitic fluid is seen in conditions such as:
- Acute pancreatitis
- Perforated intestine or duodenal ulcer
- Ruptured gallbladder or bile duct injury
Overview on cell count and differential
- Total WBC count >500 cells/mm3 indicates peritonitis
- Tuberculous peritonitis is associated with
- WBC >500 cells/mm3 with lymphocytic predominance
- Positive Ziehl-Nielsen stain
- Increased protein level
- Low glucose
- Many mesothelial cells
- Positive TB culture
- Polymorphonuclear (PMN) cell count ³250 cells/mm3 (neutrocytic ascites) may be consistent with spontaneous bacterial peritonitis, cirrhosis, secondary infection, or biliary perforation (bile-stained)
- Lymphocytic predominance suggests tuberculous peritonitis or chylous ascites
- RBC count >20,000 cells/mm3 indicates hemorrhagic fluid (TB/Malignancy/Trauma)
- In abdominal trauma, >100,000 RBC cells/mm3 is consistent with significant intra-abdominal hemorrhage
Overview on culture
- Microbiological exam can reveal coliforms, anaerobes, and enterococci, which can enter peritoneum from ruptured organs or from infections accompanying appendicitis, pancreatitis, TB, or ovarian disease
- Gram positive cocci often indicate primary peritonitis, whereas gram-negative organisms indicate secondary peritonitis
- Gram stain is usually negative in early spontaneous bacterial peritonitis, but may be positive in peritonitis due to perforation
- Tuberculosis smears and culture should be obtained if the fluid has a lymphocyte predominance and low serum-ascites albumin gradient (SAAG) or when peritoneal tuberculosis is suspected
- Conventional cultures are positive in 35-57% samples, compared to 77-93% positive when fluid is directly inoculated into blood culture bottles in patients with suspected bacterial peritonitis
- Presence of fungi may be suggestive of histoplasmosis, candidiasis, or coccidioidomycosis
Overview on cytology
- Cytologic studies may be performed when there is a lymphocytic predominance with a low SAAG, or when peritoneal carcinomatosis is suspected
Ascitic fluid profiles in various disease states:
Transudates
(Fluid protein concentration <2.5-3.0 g/dL; fluid LDH/serum LDH ratio <0.6)
| Diagnosis | Cirrhosis | Congestive heart failure | Nephrotic syndrome | Pseudomyxoma
peritonei |
|---|
| Appearance | Clear | Clear | Clear | Gelatinous |
| WBC's (cells/mm3 or /µL) | <250 | <250 | <250 | <250 |
| WBC Differential* | MN's | MN's | MN's | |
| RBC's (cells/mm3 or /µL) | Few | Few | Few | Few |
| Gram stain/Culture | Negative | Negative | Negative | Negative |
| Cytology | Negative | Negative | Negative | Occasionally positive |
| Fluid Protein (g/dL) | <3.0 | <2.5 | <2.5 | <2.5 |
Serum Ascites
Albumin Gradient (SAAG) | High (³1.1) | High (³1.1) | Low (<1.1) | - |
| Fluid Glucose (mg/dL) | Normal | Normal | Normal | Normal |
| Comments | Occasionally turbid, rarely bloody.
Fluid LDH/serum LDH ratio <0.6 | - | - | - |
* MN's = mononuclear cell predominance
Exudates
(Fluid protein concentration >2.5-3.0 g/dL; fluid LDH/serum LDH ratio >0.6)
| Diagnosis | Bacterial peritonitis | Tuberculous peritonitis | Malignancy | Pancreatitis | Chylous ascites |
|---|
| Appearance | Cloudy | Clear | Clear or bloody | Clear or bloody | Turbid |
| WBC's (cells/mm3 or /µL) | >500 | >500 | >500 | >500 | Few |
| WBC Differential* | PMN's | MN's | MN's or PMN's | MN's or PMN's | |
| RBC's (cells/mm3 or /µL) | Few | Few (rarely many) | Many | Many | Few |
| Bacteriologic Gram stain and Culture | Positive | Stain Positive in 25%; culture Positive in 65% | Negative | Negative | Negative |
| Cytology | Negative | Negative | Positive in 60-90% | Negative | Negative |
| Fluid Protein (g/dL) | >3.0 | >3.0 | >3.0 | >2.5 | Varies, often >2.5 |
| Serum Ascites Albumin Gradient (SAAG) | Low (<1.1) | Low (<1.1) | Low (<1.1) | Low (<1.1) | - |
| Fluid Glucose (mg/dL) | <50 with perforation | <60 | <60 | Normal | Normal |
| Comments | Blood cultures frequently positive | Occasionally chylous.
Peritoneal biopsy positive in 65% cases | Occasionally chylous.
Fluid LDH/Serum LDH ratio >0.6.
Peritoneal biopsy is diagnostic | Occasionally chylous.
Fluid amylase >1000 IU/L, sometimes >10,000 IU/L
Ascites amylase>serum amylase | Fluid TG >400 mg/dL (turbid)
Fluid TG > serum TG |
- * MN's=Mononuclear cells predominance
- PMN's=Polymorphonuclear cell predominance
- TG = Triglycerides
Additional information
- If there is suspicion of bladder tap rather than ascitic fluid, measure blood urea nitrogen (BUN)
- Factors interfering with test results include:
- Failure to send specimen to lab immediately
- Non-sterile collection technique for culture
- Contamination of the sample with blood, bile, urine, or feces
- Traumatic tap resulting in bloody fluids
- Drugs such as anticoagulants and aspirin
- Related laboratory tests include:
This section covers Ascites fluid - Cells/ Culture. The other section provides detailed information on other components of Ascites fluid analysis
Nl Result
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
| Conv. Units
(cells/mm3) | SI Units
(cells 109/L) |
|---|
| Total WBC's | <500 | <500 |
| Polymorphonuclear cells | <250 | <250 |
| RBC's | none | none |
- Gross appearance: Clear to straw colored
- Cytology: No malignant cells
- AFB smear/culture: Negative
- Gram stain: Negative
- Bacterial culture: Negative
- Fungal stains/culture: Negative
- For diagnostic peritoneal lavage (DPL) in trauma RBC's should be <100,000 cells/mm3
This section covers Ascites fluid - Cells/ Culture. The other section provides detailed information on other components of Ascites fluid analysis
High Result
Conditions associated with increased quantity of peritoneal fluid include
- Transudates
- Congestive heart failure
- Hepatic cirrhosis/portal hypertension
- Hypoproteinemia (nephrotic syndrome)
- Exudate
- Biliary peritonitis
- Infections
- Primary bacterial peritonitis
- Secondary bacterial peritonitis such as from appendicitis or intestinal infarction
- Tuberculosis
- Neoplasms
- Hepatoma
- Lymphoma
- Mesothelioma
- Metastatic carcinoma
- Pancreatitis
- Trauma
- Chylous effusion (damage or obstruction of thoracic duct)
- Carcinoma
- Lymphoma
- Parasitic infestations
- Trauma
- Tuberculosis
Conditions associated with >500 WBC/mm3 in peritoneal fluid include:
- Bacterial peritonitis
- Biliary perforation
- Cirrhosis
- Malignancy
- Pancreatitis
- Secondary infection
- Tuberculous peritonitis
Conditions associated with increased polymorphonuclear cells (>250 cells/mm3) in peritoneal fluid include
- Bacterial peritonitis (polymicrobial)
- Biliary perforation
- Pancreatitis
- Spontaneous bacterial peritonitis
Conditions associated with increased lymphocytes in peritoneal fluid include
- Peritoneal carcinomatosis
- Tuberculous peritonitis
Conditions associated with mononuclear cell predominance in peritoneal fluid include
- Cirrhosis
- Congestive heart failure
- Malignant peritonitis (some types)
- Nephrotic syndrome
Conditions associated with increased RBC's in peritoneal fluid include
- Intra-abdominal hemorrhage
- Malignant ascites
- Pancreatitis (some cases)
- Trauma
- Tuberculous peritonitis (some cases)
Organisms associated with peritonitis in peritoneal fluid include
- Bacterial
- Bacteroides fragilis
- Escherichia coli
- Klebsiella pneumoniae
- Mycobacterium tuberculosis
- Pseudomonas
- Staphylococcus species
- Streptococcus species
- Fungal
- Candidiasis
- Coccidioidomycosis
- Histoplasmosis
This section covers Ascites fluid - Cells/ Culture. The other section provides detailed information on other components of Ascites fluid analysis
References
- ARUP Laboratories®. Body Fluid Culture (Includes Gram Stain 0060101). [Homepage on the internet]©2007. Last accessed on August 30, 2007. Available at URL: http://www.aruplab.com/guides/ug/tests/0060108.htm
- ARUP Laboratories®. Cell Count, Body Fluid. [Homepage on the internet]©2007. Last accessed on August 30, 2007. Available at URL: http://www.aruplab.com/guides/ug/tests/0095019.htm
- ARUP Laboratories®. Cytology, Body Cavity Fluid. [Homepage on the internet]©2007. Last accessed on August 30, 2007. Available at URL: http://www.aruplab.com/guides/ug/tests/8209701.htm
- Castellote J et al. Spontaneous bacterial peritonitis and bacterascites prevalence in asymptomatic cirrhotic outpatients undergoing large-volume paracentesis. J Gastroenterol Hepatol. 2007 Aug 7; [Epub ahead of print]
- Christou L et al. Characteristics of ascitic fluid in cardiac ascites. Scand J Gastroenterol. 2007 Sep;42(9):1102-5.
- eMedicine from WebMD®. Ascites. [Homepage on the Internet] ©1996-2007. Last updated on February 21, 2007. Last accessed on August 30, 2007. Available at URL: http://www.emedicine.com/med/topic173.htm
- eMedicine from WebMD®. Paracentesis. [Homepage on the Internet] ©1996-2007. Last updated on March 14, 2006. Last accessed on August 30, 2007. Available at URL: http://www.emedicine.com/proc/topic80944.htm
- Laboratory Corporation of America®. Abdominal Fluid Cytology. [Homepage on the internet]©2007. Last accessed on August 30, 2007. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/cy003600.htm
- Laboratory Corporation of America®. Body Fluid Culture, Sterile, Routine. [Homepage on the internet]©2007. Last accessed on August 30, 2007. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/mb002700.htm
- Ribeiro TC et al. Evaluation of reagent strips for ascitic fluid leukocyte determination: is it a possible alternative for spontaneous bacterial peritonitis rapid diagnosis? Braz J Infect Dis. 2007 Feb;11(1):70-74l.
- Yamada S et al. Clinical implications of peritoneal cytology in potentially resectable pancreatic cancer: positive peritoneal cytology may not confer an adverse prognosis. Ann Surg. 2007 Aug;246(2):254-8.