A 61-year-old woman with alcohol-associated cirrhosis (MELD 3.0 = 18) is admitted with 4 days of worsening abdominal distension and low-grade fever. She has large tense ascites. Her INR is 1.8 and platelet count is 68,000/mm³. A nurse asks whether she needs FFP before the procedure. The attending asks you: "Should we tap her?"
As you read through this page, think about: what is the indication for paracentesis here, does coagulopathy change your decision, what studies do you send, and what would PMN ≥250/mm³ mean for her management?
Indications & Contraindications
▼Paracentesis is one of the safest and highest-yield procedures in clinical medicine. Every patient admitted to the hospital with cirrhosis and ascites should be considered for diagnostic paracentesis at the time of admission — regardless of whether spontaneous bacterial peritonitis (SBP) symptoms are present, because up to one-third of SBP cases are clinically silent.
Indications
New-Onset Ascites
- First presentation of ascites — determine etiology (cirrhotic vs. malignant vs. cardiac)
- Serum-ascites albumin gradient (SAAG) requires simultaneous serum and ascites albumin
- Identify unexpected infection before symptoms develop
Clinical Deterioration
- Any hospitalized patient with cirrhosis and ascites — rule out SBP at admission
- Fever, abdominal pain, encephalopathy, or leukocytosis in a patient with known ascites
- Unexplained acute kidney injury (AKI) or hemodynamic instability in a patient with cirrhosis
Large-Volume Paracentesis (LVP)
- Tense ascites causing respiratory compromise, discomfort, or early satiety
- Refractory ascites not responding to maximal diuresis
- Typically 4–6 L removed per session; albumin replacement required for >5 L removed (6–8 g per liter)
Contraindications
There are no absolute contraindications to paracentesis in a patient with clinically apparent ascites. The following are relative, and the diagnostic or therapeutic benefit almost always outweighs the risk.
- Coagulopathy (international normalized ratio [INR] > 2.0 or platelet count < 50,000/mm³) — American Association for the Study of Liver Diseases (AASLD) does not recommend routine correction of coagulopathy with fresh frozen plasma (FFP) or platelets prior to paracentesis. Complication rates are not meaningfully increased at these thresholds. Correction is only warranted if disseminated intravascular coagulation (DIC) is suspected.
- Prior abdominal surgeries — bowel adhesions alter normal anatomy; use ultrasound (US) guidance and select a site away from scars
- Active skin infection at intended site — select an alternate site; do not puncture through cellulitis or active wound
- Pregnancy — perform with real-time US guidance; use sites away from fundal height
- Ileus or significantly dilated bowel — US-guided confirmation of fluid pocket is essential
- Uncooperative patient — discuss goals of care; procedural sedation may be appropriate in select cases
Informed Consent
▼The consent discussion for paracentesis should be brief, accurate, and patient-centered. Most patients with cirrhosis and recurrent ascites will have had this procedure before — acknowledge that and focus on what is new or different about this encounter (e.g., first time, large volume, infected fluid concern).
What to Explain to the Patient
Why We Are Doing This
For a diagnostic tap: "We're going to take a small sample of the fluid in your abdomen to check for infection and to help us understand what's causing it." For a therapeutic tap: "We're going to drain a larger amount of the fluid to relieve your discomfort and make it easier to breathe."
What Will Happen
We will use ultrasound to find the best spot, numb the skin with local anesthesia, and then insert a thin needle or catheter to collect or drain the fluid. The procedure usually takes 10–20 minutes. Some pressure is normal; sharp pain is not — tell us immediately if that happens.
If You Decline
For diagnostic indications: we cannot assess for infection without a fluid sample — watchful waiting is not appropriate when SBP is in the differential. For therapeutic indications: continued diuresis may partially manage the ascites but will not produce the same relief. Explain risks of untreated infected ascites.
Risks to Disclose
- Pain or discomfort — local anesthetic minimizes this; pressure is expected; sharp pain should be reported immediately
- Bleeding or hematoma at the needle site — most are self-limited; significant bleeding is rare (<1%)
- Infection — iatrogenic peritonitis from the procedure itself is very rare (<0.1%) with sterile technique
- Bowel perforation — very rare (<0.1%) with ultrasound guidance; usually self-healing; CT scan and surgical consultation required if suspected
- Persistent ascites leak from the needle site — typically resolves with a pressure dressing; rarely requires a mattress suture
- Post-paracentesis circulatory dysfunction (PPCD) — applies to large-volume paracentesis (>5 L); compensatory neurohormonal activation can cause AKI and hyponatremia; mitigated with albumin infusion (6–8 g per liter removed)
- Failure to obtain adequate fluid — may require repositioning, alternative site, or repeat attempt
- Death — extremely rare; mention only when procedural risk is genuinely elevated
Equipment & Setup
▼Many institutions use pre-packaged commercial paracentesis kits (e.g., CareFusion, Merit Medical). Verify your kit contents against the list below and supplement as needed. Have specimen collection containers labeled and ready before the procedure begins.
Ultrasound
- Point-of-care US (POCUS) is the standard of care — do not perform paracentesis without first confirming the fluid pocket location and depth
- Curvilinear probe (3–5 MHz) for abdominal imaging
- Identify the largest accessible pocket, assess depth to peritoneum, and use Doppler to avoid abdominal wall vessels (inferior epigastric arteries)
- Mark the site with a skin marker while the patient is in the position they will hold during the procedure
Prep and Drape
- Sterile gloves (two pairs recommended — outer pair can be changed after prep)
- Chlorhexidine-alcohol or povidone-iodine prep solution
- Sterile fenestrated drape
- Sterile gauze (4×4)
Local Anesthetic
- 1% or 2% lidocaine, 5–10 mL
- 25-gauge needle for skin wheal
- 22-gauge needle for deep infiltration down to peritoneum
- 5–10 mL syringe for injection
Needles / Catheter
- Diagnostic tap: 18-gauge needle on a 20–60 mL syringe; alternatively a small over-the-needle catheter (18–20 gauge)
- Large-volume: 14–16 gauge over-the-needle catheter (e.g., Caldwell needle or kit catheter) connected to extension tubing and drainage bag or vacuum bottles
Tubes and Bottles
- Blood culture bottles (aerobic + anaerobic) — inoculate 10 mL each at the bedside before any other tubes; this is the most important step for culture yield
- EDTA (purple-top) tube — cell count with differential
- Red-top or serum separator tube — albumin, total protein, lactate dehydrogenase (LDH), glucose
- Additional tubes as indicated (see Fluid Studies section)
Dressing
- Gauze and pressure dressing for site
- Adhesive bandage or transparent dressing
- Suture (2-0 nylon) and holder — available but rarely needed for persistent leak
Site Selection
The left lower quadrant (LLQ) is the preferred default site — the spleen lies more superiorly and medially, bowel is generally less dense in the LLQ, and the left-sided approach is ergonomic for right-handed operators standing at the patient's left. The right lower quadrant (RLQ) is an acceptable alternative but carries greater risk of encountering cecum. The infraumbilical midline (linea alba) can be used when bilateral flanks are suboptimal, but avoid in patients with portal hypertension-related dilated midline veins (caput medusae).
Step-by-Step Technique
▼Click each step to review technique details. Use the navigation buttons to advance through the procedure in sequence.
Supine with slight head elevation (30°) is the standard position. For LLQ access, a slight rightward lateral tilt (left side up slightly) encourages fluid to pool in the left flank. The patient should remain still — explain this before beginning.
For tense ascites, the patient is often already in a semi-recumbent position for comfort. Confirm the intended puncture site is below the fluid level by percussion (dull to percussion) and pre-procedure US.
Expose and visualize the lower abdomen. Ensure adequate lighting. Position yourself so that your dominant hand will hold the needle and your non-dominant hand can stabilize the skin. Have an assistant available to hand you tubes and bottles during the procedure.
Perform a full pre-procedure US survey before opening any sterile equipment. Identify the largest accessible fluid pocket, note the depth from skin to fluid and from skin to bowel, and activate Doppler to map inferior epigastric vessels. Mark the planned entry site with a skin marker.
- Minimum depth: ≥ 2 cm of fluid between the peritoneum and underlying bowel is generally considered safe; deeper pockets are preferable
- Avoid: visible peristalsis, bowel loops, prior surgical scar adhesion sites, and dilated abdominal wall veins
- Real-time guidance (needle in-plane with probe during insertion) is not routinely required for standard paracentesis but should be used when the pocket is small, the patient is obese, or there is prior surgical history
- After marking, ask the patient to stay in the same position — fluid redistributes with repositioning
Open the paracentesis kit or assemble your equipment on a sterile field. Put on sterile gloves.
- Apply chlorhexidine-alcohol (or povidone-iodine) to the intended site in concentric circles moving outward from the mark, covering a generous area (>10 cm diameter)
- Allow the prep solution to fully dry before proceeding — chlorhexidine requires 30 seconds, povidone-iodine 2 minutes. Do not blot or wipe.
- Apply the sterile fenestrated drape so the puncture site is centered in the window
- Arrange all equipment within reach on your sterile field before proceeding
This is an appropriate time to confirm with your assistant that specimen tubes are labeled and blood culture bottles are open and ready at the bedside.
Adequate local anesthesia is the most important factor in patient comfort. Take your time here — a poorly anesthetized patient will move.
- Raise a skin wheal with a 25-gauge needle and 1–2 mL of 1% lidocaine at the marked site. Wait 30–60 seconds.
- Switch to a 22-gauge needle on the same syringe. With intermittent aspiration (negative pressure between injections), advance the needle perpendicular to skin, injecting 1–2 mL every few millimeters through the subcutaneous tissue and muscle layers.
- When you reach the peritoneum, you may feel a give or pop. Inject an additional 2–3 mL of lidocaine at this level — the peritoneum is the most sensitive layer and the most commonly under-anesthetized.
- If you aspirate ascitic fluid into the syringe during anesthesia: you have confirmed access depth and the needle trajectory is correct. Note the depth from skin to peritoneum for your paracentesis needle insertion.
Total lidocaine used is typically 5–10 mL. Onset is 2–3 minutes — proceed promptly once the wheal is raised but do not rush the deeper layers.
The Z-track technique minimizes the risk of persistent post-procedure ascites leak. It is the standard approach.
- With your non-dominant hand, displace the skin 1–2 cm from the marked site before inserting the needle. Maintain this traction throughout insertion.
- Insert the paracentesis needle (or over-the-needle catheter) perpendicular to skin, advancing slowly with gentle aspiration on the attached syringe. Advance through the subcutaneous tissue, then through the muscle fascia.
- At the peritoneum, you will feel a distinct give or loss of resistance and ascitic fluid will flash back into the syringe. Stop advancing immediately.
- For an over-the-needle catheter: while holding the needle still, advance the catheter off the needle and into the peritoneal cavity. Then remove the needle, leaving the flexible catheter in place.
- Release the skin traction. The skin displacement creates a non-linear track — when the needle is removed and skin returns to its natural position, the skin puncture and the fascial puncture no longer align, reducing fluid egress.
Collect fluid immediately after confirming access. The approach differs by indication.
Diagnostic tap (30–60 mL): Aspirate directly into a 20–60 mL syringe. If resistance is met, rotate the catheter or needle slightly — the tip may be against bowel or the abdominal wall. Do not apply excessive suction. Collect the volume needed for all planned studies plus culture bottles, then proceed to specimen inoculation.
Large-volume paracentesis (LVP, typically 4–6 L): Connect the catheter to extension tubing and a closed vacuum drainage system (vacuum bottles or a large collection bag). Fluid drains by gravity and vacuum — do not use suction pumps routinely, as rapid drainage can cause PPCD. Monitor the patient during drainage. Most LVPs complete within 30–90 minutes. The goal per session is typically 4–6 L; more can be removed safely with appropriate albumin replacement.
Specimen processing is the highest-yield step for infection diagnosis. The order of inoculation matters.
- Blood culture bottles first — inoculate 10 mL into each of the aerobic and anaerobic bottles at the bedside, immediately. This step alone improves culture yield from ~50% to ~80%. The bottles contain growth media that maintain bacterial viability during transport; standard red-top tubes do not.
- Distribute remaining fluid into the EDTA (purple-top) tube for cell count, and into the red-top or serum separator tube for chemistry studies.
- Send any supplemental tubes indicated by clinical context (see Fluid Studies section).
Once collection is complete:
- Remove the needle or catheter in a single smooth motion. Apply firm direct pressure with sterile gauze for 2–5 minutes to minimize hematoma and promote track closure.
- Inspect the site. Minor oozing is expected. Apply a pressure dressing.
- For LVP: initiate albumin replacement — 25% albumin, 6–8 g per liter of ascites removed beyond 5 L. Begin infusion during or immediately after drainage. This is the evidence-based standard (Sort et al., NEJM 1999) to prevent PPCD and AKI.
- Document: volume removed, appearance of fluid, studies sent, needle size and site, patient tolerance, and any complications.
- Reassess the patient 15–30 minutes after completion — check vital signs, inspect the site for expanding hematoma, and confirm the patient is comfortable.
Ascitic Fluid Studies
▼At minimum, every paracentesis should yield a cell count, albumin, total protein, LDH, glucose, and bedside-inoculated blood culture bottles. Supplemental studies are ordered based on clinical suspicion and the SAAG result.
| Study | Tube / Method | Key Threshold / Interpretation |
|---|---|---|
| Routine — Send on Every Tap | ||
| Routine Cell count with differential | EDTA (purple-top) | Polymorphonuclear neutrophil (PMN) count ≥ 250/mm³ = SBP; treat immediately without waiting for culture. Also assess for lymphocyte predominance (tuberculous peritonitis, malignancy). |
| Routine Albumin | Red-top or SST | Required to calculate SAAG (serum albumin − ascites albumin). Both serum and ascites samples must be drawn at the same time. SAAG ≥ 1.1 g/dL = portal hypertension (97% accuracy). |
| Routine Total protein | Red-top or SST | Ascites protein < 1.5 g/dL = low opsonic activity → SBP risk; key criterion for primary SBP prophylaxis eligibility. Protein > 2.5 g/dL in high-SAAG ascites → cardiac/vascular etiology (vs. cirrhotic). |
| Routine LDH + Glucose | Red-top or SST | Required for Runyon's criteria for secondary peritonitis: LDH > upper limit of normal for serum AND glucose < 50 mg/dL (two or more Runyon criteria = suspect secondary peritonitis). |
| Routine Culture (bedside inoculation) | 10 mL aerobic + 10 mL anaerobic blood culture bottles, inoculated at bedside | Bedside inoculation improves yield from ~50% to ~80%. Positive monomicrobial culture + PMN ≥ 250 = classic SBP. Polymicrobial growth = strongly suspect secondary peritonitis or needle bowel contamination. |
| Selective — Order When Clinically Indicated | ||
| Selective Amylase | Red-top or SST | Markedly elevated (>1,000 U/L, often >3× serum) = pancreatic ascites from ductal disruption. Useful in pancreatitis with new ascites or failed response to SBP treatment. |
| Selective Triglycerides | Red-top or SST | > 200 mg/dL = chylous ascites (lymphatic disruption). Fluid will appear milky or opalescent. Etiologies: lymphoma, retroperitoneal surgery, trauma. |
| Selective Bilirubin | Red-top or SST | Ascites bilirubin > serum bilirubin (typically ≥ 2×) = biliary ascites from bile duct leak. Fluid appears bile-tinged or golden. Requires ERCP (endoscopic retrograde cholangiopancreatography) or surgical repair. |
| Selective Cytology | Large-volume collection (50–100 mL) in a plain tube or cytology container | Positive in ~65–80% of peritoneal carcinomatosis. Sensitivity improves with volume. Send when malignant ascites is suspected and SAAG < 1.1 g/dL. False negatives are common — peritoneal biopsy may be required. |
| Selective Adenosine deaminase (ADA) | Red-top or SST | > 30–40 U/L = high sensitivity for tuberculous peritonitis in endemic populations. Low specificity in cirrhotic ascites (many false positives). Best used in low-SAAG, lymphocyte-predominant ascites in a patient from a TB-endemic region. |
| Selective Gram stain | Submitted with culture bottles | Rarely positive in SBP (sensitivity < 10%) — bacteria are present in very low concentrations. A positive Gram stain with multiple organisms strongly suggests secondary peritonitis or procedural bowel contamination. |
Complications & Management
▼Paracentesis performed with US guidance and sterile technique has an excellent safety profile. The most common complication is minor abdominal wall bleeding — almost always self-limited. Life-threatening complications are rare and most are preventable.
| Complication | Frequency | Management |
|---|---|---|
| Abdominal wall hematoma | ~1% | Apply firm, sustained pressure (5–10 min). If expanding or hemodynamically significant: US or CT to characterize; interventional radiology (IR) embolization for ongoing arterial bleeding. Pre-procedure Doppler reduces incidence. |
| Persistent ascites leak | <1% | Z-track technique is the primary prevention. If leak persists > 30 min: close the skin puncture with tissue adhesive (dermabond) or a figure-of-eight suture (2-0 nylon). |
| Post-paracentesis circulatory dysfunction (PPCD) | ~20% if >5 L without albumin | Prevented by albumin infusion: 25% albumin, 6–8 g per liter removed beyond 5 L. If PPCD occurs (AKI, hyponatremia, hemodynamic instability): volume expansion, hold diuretics and nephrotoxins, reassess renal function daily. Consider hepatorenal syndrome (HRS) workup if creatinine rises. |
| Bowel perforation | <0.1% with US guidance | Suspect if: feculent fluid, frank peritonitis signs post-procedure, or Gram stain with multiple organisms. Order CT abdomen/pelvis immediately. Surgical consultation is required. Most small-needle perforations self-seal in the bowel wall; larger punctures or thin-walled bowel may require surgical repair. |
| Iatrogenic infection | <0.1% | Extremely rare with proper sterile technique. If post-procedural peritonitis is suspected: repeat paracentesis for cell count and culture. Distinguish from SBP discovered on the original tap versus new infection introduced by the procedure. |
| Significant hemorrhage | <0.1% | True large-vessel injury is exceedingly rare. Risk is not meaningfully elevated by abnormal coagulation studies in cirrhosis — do not transfuse prophylactically. If hemorrhage occurs: type and cross, IR evaluation, surgical backup. Resuscitate while characterizing source. |
Returning to the case from the top of the page: 61-year-old woman with alcohol-associated cirrhosis (Child-Pugh B, MELD 3.0 = 18), admitted with 4 days of worsening abdominal distension and low-grade fever. INR 1.8, platelets 68,000/mm³.
- Indication: Hospitalized patient with cirrhosis and ascites + fever → diagnostic paracentesis is mandatory at admission, regardless of whether she has abdominal pain. Clinical silence does not exclude SBP.
- Consent: Acknowledge prior paracentesis, briefly review risks (bleeding, infection, leak), explain that the culture bottles are placed at the bedside this time (highlight improvement in practice). Confirm understanding.
- Lab review: INR 1.8, platelet count 68,000/mm³. Do not transfuse FFP or platelets — not indicated. Proceed.
- Setup: US confirms a 6 cm LLQ fluid pocket at 3.5 cm depth. Doppler shows no vessels at the intended entry point. Mark and prepare. Assemble aerobic + anaerobic blood culture bottles at bedside before starting.
- Result: 60 mL of straw-colored fluid aspirated. PMN 310/mm³ (no RBC, no traumatic tap correction needed). Culture bottles inoculated immediately. Chemistry tubes sent.
- Interpretation: PMN ≥ 250 → SBP. Start ceftriaxone 2 g IV now. Do not wait for culture. Check creatinine, blood urea nitrogen (BUN), bilirubin — if any elevated, begin albumin 1.5 g/kg day 1 + 1 g/kg day 3. Hold diuretics.
- Teaching point: The patient had a diagnostic paracentesis three months ago. The chart shows her ascites protein was 1.3 g/dL at that time and her creatinine was 1.4 mg/dL — she met criteria for primary SBP prophylaxis (protein <1.5 g/dL + creatinine ≥ 1.2 mg/dL) and was not started on it. This hospitalization was potentially preventable.
- Biggins SW, Angeli P, Garcia-Tsao G, et al. Diagnosis, evaluation, and management of ascites, spontaneous bacterial peritonitis and hepatorenal syndrome: 2021 practice guidance by the American Association for the Study of Liver Diseases. Hepatology. 2021;74(2):1014-1048. PubMed 33942342
- Sort P, Naveau M, Arroyo V, et al. Effect of intravenous albumin on renal impairment and mortality in patients with cirrhosis and spontaneous bacterial peritonitis. N Engl J Med. 1999;341(6):403-409. PubMed 10432325
- Runyon BA, Montano AA, Akriviadis EA, et al. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med. 1992;117(3):215-220. PubMed 1616215
- Mercaldi CJ, Lanes SF. Ultrasound guidance decreases complications and improves the cost of care among patients undergoing thoracentesis and paracentesis. Chest. 2013;143(2):532-538. PubMed 23381318