New Ascites That Is Moderate or Large
Diagnostic paracentesis is considered mandatory when a person has new grade 2 or 3 ascites. These grades describe larger amounts of fluid. The test checks the fluid for infection and helps show why it formed.
AI Summary Diagnostic paracentesis uses a needle to take a fluid sample from the abdomen when a person has ascites, most often from cirrhosis. The lab checks cell count, protein, albumin, and bacteria to look for infection (SBP) and help find the cause. The test usually takes 20 to 60 minutes, and most people go home the same day. Risks include bleeding, infection, and low blood pressure. Bring your symptoms and medicine list to your visit.
Source: www.liverdirectory.com
Diagnostic Paracentesis
Medically Reviewed.
Diagnostic paracentesis is a procedure in which a needle removes a sample of fluid from the abdomen. The lab then tests that fluid. Doctors use it when a person has ascites, a buildup of fluid in the abdomen that is often linked to advanced liver disease.
The lab checks the fluid for cells, protein, albumin, and bacteria. These results can show whether the fluid is infected and can help explain why it formed.
This page explains when doctors order the test, how it works, what the results can show, what the risks are, and how to prepare for your visit.
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Ascites fluid test basics
What Is Diagnostic Paracentesis?
Diagnostic paracentesis is a test that samples ascitic fluid, the fluid that builds up in the abdomen in ascites. A doctor passes a needle through the skin of the abdomen and draws out a sample. The sample goes to a lab, which measures its cell count, protein, and albumin and grows a culture to look for bacteria. These are the key measures that guide diagnosis and care.
Ascites is not a disease. It is a symptom of another condition. Advanced liver disease and cirrhosis are the most common causes, and nearly 80% of ascites cases occur in people with cirrhosis. Ascites forms when pressure rises in the blood vessels of the liver (portal hypertension) and the blood level of the protein albumin falls. You can read more on the Ascites and Portal Hypertension pages.
A physical exam can often show that ascites is present. Testing the fluid answers different questions: Is it infected? What is causing it? Diagnostic paracentesis is one of several ascites tests.
Diagnostic Paracentesis at a Glance
- Purpose: to test ascitic fluid for infection and to help find the cause of the fluid buildup.
- What the lab measures: cell count, protein, albumin, and bacterial culture.
- Who needs it: the test is considered mandatory for new grade 2 or 3 ascites and for anyone hospitalized with a cirrhosis-related complication.
- Infection threshold: a neutrophil count above 250 cells per microliter of fluid is the diagnostic cutoff for spontaneous bacterial peritonitis (SBP).
- Time and recovery: paracentesis usually takes 20 to 60 minutes, and most people go home the same day.
Your care team interprets results alongside your symptoms, exam, and other tests.
Ascites testing guidelines
When Doctors Order Diagnostic Paracentesis
A Hospital Stay for a Cirrhosis Complication
The test is also called for in anyone hospitalized for a cirrhosis-related complication. SBP can cause no symptoms in up to 3.5% of outpatients, and a diagnosis made more than 12 hours after admission is linked to a 2.7-fold higher risk of death. Early testing lets doctors treat infection quickly.
Fluid with an Unclear Cause
Ascites has many possible causes, including cirrhosis, hepatitis C, long-term heavy alcohol use, heart failure, pancreatitis, certain cancers, and blood clots in the liver's veins. Tests on the fluid help check for other troublesome conditions beyond liver disease.
Fluid Removal for Symptom Relief
Your provider may take a fluid sample during the same visit as a procedure to relieve belly swelling, discomfort, or trouble breathing. See the [Paracentesis](/liver-therapies/interventional-procedures/portal-hypertension-procedures/paracentesis) and [Large-Volume Paracentesis](/liver-therapies/liver-disease-complication-management/ascites/large-volume-paracentesis) pages for that treatment.
Ascitic fluid lab analysis
What the Lab Checks in the Fluid
These are the main measures taken from a fluid sample.
- Cell Count
- The lab counts cells in the fluid. A high count of neutrophils, a type of white blood cell that fights infection, points to spontaneous bacterial peritonitis (SBP).
- Protein
- The lab measures the amount of protein in the fluid. This result helps doctors narrow down the cause of the ascites.
- Albumin
- The lab measures albumin in the fluid. Albumin is a protein the liver makes. Doctors use it to help guide the diagnosis. See [Ascites Testing](/liver-tests/liver-complication-testing/ascites-testing) for related albumin tests.
- Culture
- The lab places fluid in culture bottles to see whether bacteria grow. A positive culture can confirm infection, even when a person has no symptoms.
Fluid test results explained
What Your Results Can Mean
A High Neutrophil Count or Positive Culture
SBP is an infection of ascitic fluid with no clear infection source elsewhere in the abdomen. It is diagnosed when the neutrophil count is 250 cells per cubic millimeter or higher, or when cultures are positive. Your care team treats SBP urgently.
Results Without Signs of Infection
A count below the cutoff and a negative culture suggest the fluid is not infected. Your doctor still reviews protein and albumin results, your symptoms, and your other tests to find the cause of the fluid.
Putting Results in Context
No single number decides your care. Ask your provider which results matter most for you and what the next step is. Treatment of the fluid buildup itself is covered on the [Ascites](/liver-therapies/liver-disease-complication-management/ascites) page.
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Paracentesis procedure steps
What Happens During the Procedure
Diagnostic paracentesis is minimally invasive and usually takes 20 to 60 minutes, depending on how much fluid is removed.
- Your provider examines your abdomen. They may use ultrasound to find a safe pocket of fluid.
- They clean the skin and numb it with a local anesthetic.
- They insert a needle or thin catheter into the abdomen and draw out a fluid sample. For a test only, this is a small amount.
- The sample goes to the lab for cell count, protein, albumin, and culture.
- Your team watches you briefly afterward and tells you when results are expected.
Most people go home the same day unless they need more monitoring. If large amounts of fluid are also removed for comfort, your team may give intravenous albumin and check your blood pressure and kidney function afterward.
Paracentesis visit checklist
How to Prepare for Your Visit
- Write down your symptoms, such as belly swelling, pain, fever, weight gain, or trouble breathing, and when they started.
- List your medicines, including diuretics such as [Lasix (Furosemide)](/liver-therapies/liver-disease-complication-management/ascites/lasix) or [Aldactone (Spironolactone)](/liver-therapies/liver-disease-complication-management/ascites/aldactone), and any supplements.
- Ask your care team whether you need to change eating, drinking, or medicines before the procedure.
- Ask who will explain your results and when.
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Common questions
Answers to Common Diagnostic Paracentesis Questions
What is diagnostic paracentesis used for?
Doctors use it to test ascitic fluid for infection and to help find why the fluid formed. The lab checks cell count, protein, albumin, and culture. The cell count and culture can show spontaneous bacterial peritonitis (SBP), an infection of the fluid. Protein and albumin results help narrow down the cause of the ascites. A physical exam can often show that ascites is present, so the fluid test answers different questions: whether the fluid is infected and what is causing it.
Does everyone with ascites need a diagnostic paracentesis?
Not always, but it is often needed. It is considered mandatory for new grade 2 or 3 ascites, which are larger amounts of fluid, and for anyone hospitalized with a cirrhosis-related complication. The reason is that SBP can cause no symptoms, so testing the fluid is how doctors find it early. Your doctor decides based on your situation, including how much fluid you have and why you are in care.
What does a high white blood cell count in ascitic fluid mean?
A neutrophil count of 250 cells per cubic millimeter or higher, or a positive culture, means SBP, an infection of the ascitic fluid. Neutrophils are white blood cells that fight infection, so a high count in the fluid points to infection. SBP is diagnosed when there is no clear source of infection elsewhere in the abdomen. It needs urgent treatment, and it can occur without symptoms. Your care team will explain what the result means for you and what happens next.
Is diagnostic paracentesis painful?
The skin is cleaned and numbed with a local anesthetic before the needle goes in. Your provider may use ultrasound to find a safe pocket of fluid first. For a test only, they take a small amount of fluid, and the whole procedure usually takes 20 to 60 minutes, depending on how much fluid is removed. Ask your provider what to expect, and tell the team if you feel pain during the procedure.
What are the risks of diagnostic paracentesis?
Risks include bleeding, infection, low blood pressure, fluid leaking from the puncture site, and, rarely, kidney dysfunction. Your team monitors your blood pressure, kidney function, and symptoms before and after the procedure. If large amounts of fluid are removed, they may give intravenous albumin to help maintain circulation and kidney function. Call your care team if you have fever, worsening belly pain, bleeding, or leaking fluid afterward.
Medical disclaimer: LiverDirectory provides educational information and a directory of providers. It does not provide medical advice, diagnosis, or treatment. Always consult a licensed physician regarding any medical condition.