Ultrasound-Guided Fine Needle Aspiration in Small Animals: Techniques and Safety

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Ultrasound-guided fine needle aspiration (FNA) is a minimally invasive diagnostic procedure for intrathoracic and intra-abdominal lesions in small animals, enabling cytologic sampling to differentiate neoplasia, inflammation, infection, or benign processes, thereby guiding subsequent therapeutic decisions.
• Optimal needle selection involves a 22 G needle for solid lesions and 20-22 G for cystic structures, with lengths of 1.5 to 3.75 cm depending on target depth; a freehand technique with the needle parallel to the transducer's long axis is recommended for continuous tip visualization.
• Patient preparation includes clipping, aseptic skin preparation, and sedation or general anesthesia to ensure patient immobility, with careful assessment of coagulation status being a critical prerequisite to mitigate hemorrhage risk.
• Sample handling is paramount; aspirates should be expelled onto glass slides, smeared immediately, air-dried, and submitted with complete signalment and lesion description, with additional smears for specific staining and rinses for culture or flow cytometry as indicated.
• Major contraindications include uncorrected coagulopathy, an uncooperative patient, or an inaccessible target with an unsafe needle path, and potential complications such as hemorrhage and pneumothorax require prompt recognition and management.
• The diagnostic yield is influenced by lesion type and technique; while FNA is a reliable first-line method for splenic masses, cytologic and histopathologic diagnoses may not always agree, underscoring their complementary roles.

Ultrasound-guided fine needle aspiration (FNA) is a core diagnostic procedure in small animal practice, permitting cytologic sampling of intrathoracic and intra-abdominal lesions with minimal morbidity. This article provides a step-by-step technical guide for the practicing veterinarian, covering patient preparation, transducer and needle selection, real-time sampling technique, and specimen handling. The focus is on abdominal and thoracic applications, with attention to lesion-specific considerations and complication avoidance.

The procedure answers a specific clinical question: does this ultrasonographically detected mass, organomegaly, or fluid-filled structure represent neoplasia, inflammation, infection, or a benign process? Cytologic interpretation guides subsequent decisions regarding surgical resection, medical therapy, or additional biopsy. For many lesions, ultrasound-guided FNA provides a definitive diagnosis without the cost or risk of surgical biopsy. The technique is also used therapeutically, as in drainage of pancreatic pseudocysts, where diagnostic aspiration and therapeutic decompression are combined in a single procedure.

This reference assumes familiarity with basic ultrasound physics, transducer manipulation, and normal sonographic anatomy. It does not cover freehand abdominocentesis, cystocentesis, or thoracocentesis performed without image guidance, nor does it address endoscopic ultrasound-guided FNA, which is described in the human literature and has limited veterinary application.

At a Glance

Rationale for Ultrasound Guidance

Ultrasound guidance offers real-time confirmation that the needle tip is within the target lesion before aspiration begins. This is particularly valuable for small, deep, or mobile lesions that cannot be palpated or localized by external landmarks. The modality also permits selection of a safe needle path that avoids major vessels, bowel, and other critical structures.

The diagnostic yield of ultrasound-guided FNA depends on both the technique and the lesion type. In a prospective study of 41 dogs with splenic lesions, all 40 FNA samples were diagnostic, whereas needle core biopsy was nondiagnostic in 12.5% of cases. This finding supports FNA as a reliable first-line sampling method for splenic masses. However, the same study reported complete cytologic and histologic agreement in only 51.4% of dogs, with disagreement in 40%, underscoring that cytology and histopathology are complementary instead of interchangeable.

For bone lesions, ultrasound-guided FNA can be diagnostic when the lesion has broken through the cortex and is associated with an extraosseous soft tissue component. In a preliminary report of 23 patients, cytologic diagnosis of neoplasia was conclusive in 11 patients without need for core biopsy, and FNA was diagnostic for sarcoma in one patient where tissue core biopsy was inconclusive. However, five FNA samples were nondiagnostic despite confirmed neoplasia, indicating that negative cytology does not exclude malignancy and that core biopsy remains necessary in selected cases.

Patient Preparation and Positioning

Patient preparation begins with a focused physical examination, including assessment of coagulation status. A history of spontaneous bruising, petechiation, or prior bleeding complications warrants a platelet count and buccal mucosal bleeding time before the procedure. The evidence base for routine coagulation testing before FNA is limited, but clinical judgment should prevail in patients with suspected coagulopathy.

Sedation or general anesthesia is recommended for most patients. The procedure requires the patient to remain still during needle placement, and movement during aspiration can cause laceration of the target organ or adjacent vessels. For cooperative patients with superficial lesions, sedation alone may suffice. For deep abdominal lesions, lesions near the diaphragm, or fractious patients, general anesthesia is safer.

The hair over the proposed needle entry site is clipped, and the skin is prepared with chlorhexidine or povidone-iodine using standard aseptic technique. Ultrasound gel is applied to the transducer, which should be covered with a sterile sleeve or probe cover. Sterile gel or saline is used as the coupling medium between the probe cover and the skin. Alcohol should not be used as a coupling agent because it causes patient discomfort and can create ultrasound artifacts.

Equipment Selection

Transducer selection depends on target depth and patient size. A microconvex or curvilinear transducer operating at 5 to 8 MHz is suitable for most abdominal lesions in dogs and cats. A linear transducer at 7 to 15 MHz provides superior near-field resolution for superficial lesions, such as peripheral lymph nodes or masses within the body wall. For thoracic lesions, a microconvex transducer allows intercostal access with a smaller footprint.

Needle selection is guided by lesion characteriztics. A 22 G needle is appropriate for most solid lesions. Smaller needles, such as 25 G, may be used for highly vascular organs or for patients with thrombocytopenia, but they are more likely to yield insufficient cellular material. Larger needles, such as 20 G, are reserved for cystic lesions or for masses with dense fibrous stroma that resist aspiration. Needle length should be sufficient to reach the deepest margin of the lesion with the hub remaining outside the patient.

The choice between a standard hypodermic needle and a spinal needle depends on the needle path. A spinal needle with a stylet is useful when the path crosses body wall or when the target is deep, because the stylet prevents coring of subcutaneous tissue and reduces the risk of contaminating the sample.

Needle Selection and Sample Acquisition

The choice of needle is governed by lesion location, suspected tissue type, and the risk of hemorrhage. For most abdominal and thoracic masses, a 22 gauge, 1 to 1.5 inch needle attached to a 6 or 12 mL syringe provides adequate cellular yield with acceptable tissue trauma. Use a 25 gauge needle for highly vascular organs such as the spleen, for lesions adjacent to major vessels, or when the patient has a documented coagulopathy. Use an 18 or 20 gauge needle only when a core biopsy is intended, as larger gauge aspiration needles increase hemorrhage risk without improving cytologic quality.

For cystic lesions, including pancreatic pseudocysts, use an 18 or 20 gauge needle to permit drainage of viscous fluid. The ultrasonographic and clinicopathologic findings in pancreatic pseudocysts reported by VanEnkevort and colleagues describe successful aspiration of cysts ranging from 2 x 2 cm to 7 x 6 cm with no associated morbidity, supporting the safety of this approach when the needle path avoids intervening vessels.

The technique itself follows a consistent sequence. With the lesion centered in the ultrasound beam, advance the needle along the planned trajectory using a freehand or needle-guide technique. The needle tip is identified as a hyperechoic line with distal ring-down artifact. Once the tip is within the lesion, apply gentle suction while moving the needle in short, rapid strokes of 5 to 10 mm. Release suction before withdrawing the needle to prevent aspiration of the needle tract contents. For highly cellular or vascular lesions, capillary sampling without suction often yields superior specimens with less blood contamination.

Sample Handling and Smear Preparation

The quality of the cytologic specimen depends more on smear preparation than on the aspiration technique itself. Expel the needle contents onto a clean glass slide using an air-filled syringe. Use a second slide to gently spread the sample, preserving cell morphology. Prepare at least four to six smears to allow for multiple staining methods and to provide material for ancillary testing if needed.

Air-dry all smears rapidly. Do not use fixative sprays on smears intended for Romanowsky-type stains. If the lesion is suspected to be of endocrine origin, such as a thyroid or adrenal mass, prepare additional smears for alcohol fixation and Papanicolaou staining. Submit the remaining needle rinse in sterile saline for culture if infection is in the differential, and consider submitting a portion in formalin for histopathology or flow cytometry when lymphoma is suspected.

Record the gross appearance of the aspirate, including color, turbidity, and the presence of blood or necrotic debris. This information is diagnostically relevant. A serosanguineous aspirate from a splenic mass, for example, may represent hemodilution or a hemangiosarcoma, and the distinction affects interpretation.

Site-Specific Considerations

Abdominal Masses

For hepatic masses, sample the lesion periphery instead of the center, as central necrosis is common. The combined ultrasound-guided fine-needle aspiration and needle core biopsy of the canine spleen reported by Watson and colleagues found no complications in 38 dogs undergoing splenic sampling, but also documented disagreement between cytologic and histopathologic diagnoses in 40 percent of cases. This discordance supports the practice of obtaining both cytology and histology when the clinical picture is ambiguous, and it cautions against overinterpreting a single negative cytologic result.

Gastric wall lesions require particular care. The ultrasonographic features of canine gastric epithelial neoplasia described by Penninck and colleagues include transmural thickening with altered wall layering, and the authors noted that ultrasound-guided sampling contributed to diagnosis in their case series. When targeting the gastric wall, use a 22 gauge needle and limit the number of passes to reduce the risk of perforation. The stomach is mobile, so confirm the lesion position immediately before needle insertion.

Thoracic Lesions

Thoracic masses present the added constraint of the pleural space. A pneumothorax is the principal complication, and its risk increases with lesion depth and with the number of passes. Use the shortest needle that reaches the lesion, and consider a 25 gauge needle for peripheral pulmonary masses. The needle path should cross the minimum amount of aerated lung. If the lesion is pleural or mediastinal, an intercostal approach with the needle angled to avoid the intercostal vessels is preferred.

For mediastinal masses, the cranial mediastinum is accessible from a right or left thoracic approach depending on lesion location. The endoscopic ultrasound-guided fine-needle aspiration training model developed by Fritscher-Ravens and colleagues used porcine lymph nodes to teach puncture technique, and their finding that trainees improved with repeated procedures underscores the value of deliberate practice before performing these procedures on clinical patients.

Bone Lesions

Ultrasound-guided aspiration of bone lesions is feasible when the lesion has broken through the cortex or when the periosteum is elevated. The preliminary report on ultrasound-guided fine-needle aspiration biopsy of bone lesions by Samii and colleagues documented diagnostic samples in a majority of cases, but also noted nondiagnostic results in five of 23 patients where histopathology confirmed neoplasia. This limitation should be discussed with the owner before the procedure, and a plan for core biopsy should be in place if cytology is inconclusive.

Procedure Checklist

Troubleshooting Common Complications

Hemorrhage is the most frequent complication and is usually self-limiting. Apply firm manual pressure for 5 minutes after splenic or hepatic aspiration. If free abdominal fluid appears during the procedure, scan for an active bleed and monitor the patient's perfusion parameters. Coagulopathy is a relative contraindication, and the procedure should be deferred until the underlying disorder is addressed.

Pneumothorax after thoracic aspiration may be immediate or delayed. Scan the pleural space for a glide sign immediately after needle withdrawal. If a pneumothorax is detected, the volume is typically small and resolves with cage rest and oxygen supplementation. A tension pneumothorax requires immediate thoracocentesis.

Needle tract seeding is a theoretical concern with neoplastic lesions, particularly with sarcomas and transitional cell carcinoma. The American College of Veterinary Radiology resources on interventional procedures note that the risk is low but not zero, and the decision to aspirate a suspected sarcoma should weigh the diagnostic benefit against this possibility. When seeding is a concern, plan the needle path so that it can be excised en bloc if surgery follows.

Perforation of a hollow viscus is rare when the needle path is confirmed in real time. If the stomach or bowel is inadvertently punctured, the patient should be monitored for peritonitis over the following 24 to 48 hours. The MSD Veterinary Manual provides guidance on monitoring parameters for suspected peritonitis, including serial abdominal ultrasound, leukocyte counts, and peritoneal fluid analysis.

Documentation and Reporting

Record the following in the medical record: patient signalment and relevant history, the indication for aspiration, the lesion location and ultrasonographic appearance, the needle gauge and number of passes, the gross appearance of the sample, and any complications encountered. Include representative ultrasound images showing the needle tip within the lesion. This documentation supports cytologic interpretation, provides a baseline for follow-up imaging, and creates a record that is defensible if the procedure is questioned.

The American Veterinary Medical Association practice resources emphasize the importance of informed consent and procedural documentation in veterinary practice. Obtain written consent before the procedure, and specifically note the risk of hemorrhage, pneumothorax, and the possibility of a nondiagnostic sample. If the patient is on antiplatelet or anticoagulant therapy, document the discussion of bleeding risk and the decision to proceed or defer.

Recognized Complications and Early Detection

Most ultrasound-guided fine needle aspiration procedures in small animals are well tolerated, but complications do occur. The most frequently recognized adverse events are hemorrhage, pneumothorax, infection, and needle tract seeding.

Hemorrhage is the most common complication. It ranges from mild perilesional echogenic fluid accumulation to clinically significant blood loss. Early detection relies on continuous real-time observation of the needle tip during withdrawal and immediate post-procedural scanning of the puncture site for 30 to 60 seconds. Echogenic swirling fluid appearing in the target organ or body cavity during or immediately after aspiration indicates active bleeding. In a prospective study of combined splenic fine needle aspiration and needle core biopsy in 41 dogs, no complications were encountered in the 38 dogs assessed for safety, which suggests that splenic sampling carries a low risk of clinically important hemorrhage when performed with ultrasound guidance Safety and correlation of test results of combined ultrasound-guided fine-needle aspiration and needle core biopsy of the canine spleen. That finding does not eliminate the need for vigilance, particularly in patients with coagulopathies, thrombocytopenia, or highly vascular lesions.

Pneumothorax is the principal risk for thoracic and cranial abdominal lesions. The diaphragm should be identified before any approach to a liver or stomach mass that extends cranially. If the needle traverses lung, the patient may cough, become tachypnoeic, or show a sudden drop in thoracic wall compliance on the ultrasound image. Post-procedural thoracic ultrasound can detect a small volume of pleural air as a reverberation artefact with loss of the normal glide sign. Thoracic radiographs remain the definitive test when pneumothorax is suspected.

Infection is uncommon when aseptic technique is maintained. The needle should never pass through bowel, and the skin entry site should be clipped and prepared as for surgery. Fever, lethargy, or worsening pain in the 24 to 72 hours after sampling should prompt re-evaluation.

Needle tract seeding is a recognized but rare complication. It has been reported most often with transitional cell carcinoma of the urinary bladder and with some splenic or hepatic malignancies. The risk is reduced by limiting the number of needle passes, using the smallest gauge needle that will yield diagnostic material, and avoiding aspiration of cystic or necrotic tumor regions where viable cells may be more readily dislodged.

Common Errors and Corrective Action

Less experienced operators commonly make several predictable errors. The first is advancing the needle without continuously visualizing the tip. The needle shaft may appear within the image plane while the tip has already passed beyond the lesion. Rotating the transducer to confirm the tip in two orthogonal planes before aspirating reduces this risk.

The second error is applying excessive suction. High negative pressure collapses cellular material and produces hemodilute smears. For solid lesions, capillary action without suction often yields superior cellularity. Suction should be reserved for cystic lesions or when the first capillary pass is acellular.

A third error is sampling the center of a large mass. Central necrosis is common in tumors larger than 3 cm. The periphery of the lesion, where viable cells are concentrated, is more likely to yield diagnostic material. This is particularly relevant for splenic and hepatic masses.

Finally, operators may underestimate the value of rapid on-site evaluation. If a clinical pathologist or trained technician is available to assess smear adequacy immediately, the number of passes can be reduced and diagnostic yield improved. When this is not available, the operator should prepare at least two smears per pass and assess gross specimen quality before deciding whether to repeat.

Limitations of the Evidence

The veterinary literature on ultrasound-guided fine needle aspiration consists largely of retrospective case series and small prospective studies. Randomised controlled trials comparing FNA with needle core biopsy or surgical biopsy across multiple organ systems are lacking. The splenic study cited above is one of the few prospective evaluations, and it demonstrated that cytology and histopathology agree completely in only about half of cases Safety and correlation of test results of combined ultrasound-guided fine-needle aspiration and needle core biopsy of the canine spleen. This discordance is not necessarily an error in either method. Cytology and histopathology sample different tissue volumes, and inflammatory or reactive processes may be misclassified when only one modality is used.

For bone lesions, the evidence base is similarly limited. A preliminary study of ultrasound-guided FNA of bone lesions in 22 dogs and one cat found that diagnostic cytology could avoid tissue core biopsy in some patients, but five of 23 samples were non-diagnostic despite confirmed neoplasia Ultrasound-guided fine-needle aspiration biopsy of bone lesions: a preliminary report. A negative or non-diagnostic FNA of a bone lesion therefore does not exclude malignancy, and histopathology should be pursued when clinical suspicion remains high.

Expert opinion still differs on several points. The optimal needle gauge for specific lesions is debated, with some authorities favouring 22 gauge for all solid masses and others recommending 25 gauge for highly vascular organs. The role of aspiration versus capillary technique remains contested. Some clinicians advocate a single pass with multiple needle redirects within the lesion, while others prefer separate passes to reduce hemodilution. Neither approach has been subjected to rigorous comparative study in veterinary patients.

Training in ultrasound-guided FNA is another area where evidence is extrapolated from human medicine. Simulation models using porcine tissue have been shown to improve trainee performance in endoscopic ultrasound-guided FNA, with measurable reductions in procedure time after approximately 30 supervised procedures Learning curve for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic lesions in a novel ex-vivo simulation model. Similar data do not exist for percutaneous ultrasound-guided FNA in small animals, and the learning curve for freehand needle guidance is likely to be longer than for endoscopic approaches where the needle exit port is fixed relative to the transducer.

Referral and Escalation

Referral to a specialist should be considered when the target lesion is not safely accessible with the operator's current skill level, when a previous attempt has failed to yield diagnostic material, or when the patient has a coagulopathy that cannot be corrected. Lesions adjacent to major vessels, the heart, or the hilus of the kidney or spleen warrant particular caution. A veterinary radiologist or surgeon with interventional experience may achieve diagnostic samples where a general practitioner cannot, and may offer alternative techniques such as ultrasound-guided needle core biopsy or contrast-enhanced ultrasound to guide sampling.

Laboratory involvement is appropriate when cytology results are equivocal, when a mesenchymal neoplasm is suspected, or when the sample is poorly cellular despite adequate technique. Immunocytochemistry, flow cytometry, or PCR-based antigen receptor rearrangement testing may be required to distinguish reactive lymphoid hyperplasia from lymphoma, and these tests have specific sample handling requirements that should be confirmed with the laboratory before collection.

Regulatory reporting is rarely required for complications of ultrasound-guided FNA. However, if a biopsy is performed on an animal that is subsequently found to have a notifiable disease, such as certain zoonotic or transboundary infections, local veterinary authorities should be informed. The WOAH terrestrial animal health standards provide a framework for disease notification obligations that vary by jurisdiction. Practitioners should also be aware that some regional veterinary boards require reporting of adverse events associated with diagnostic procedures, particularly when they result in patient death or permanent injury.

Frequently Asked Questions

How many passes should I perform when sampling a solid abdominal mass?

For solid masses, two to four passes usually provide adequate cellularity. The first pass often yields the most diagnostic material, but additional passes compensate for sampling error within heterogeneous lesions. Stop when grossly visible material appears on the needle hub or when the smear shows sufficient cellularity on rapid assessment. For cavitated or necrotic regions, sample the solid periphery instead of the center. If the lesion is small, fewer passes reduce the risk of obscuring hemorrhage. The splenic sampling study by Watson et al. reported no complications with combined aspiration and core biopsy, suggesting that multiple passes are generally well tolerated in that organ.

What should I do if I only have a low-frequency curvilinear probe available?

Low-frequency curvilinear probes can guide aspiration of deep abdominal lesions, but their larger footprint reduces needle visibility and makes shallow or superficial targets difficult to access. Use the probe's needle guide if available, or align the needle parallel to the long axis of the transducer face so the shaft remains within the imaging plane. For superficial lesions, consider a standoff pad or a water bath to bring the target into the probe's focal zone. If the lesion is too small or the needle cannot be visualized reliably, convert to a blind or palpation-guided approach only when the target is fixed and superficial. ACVR resources provide guidance on probe selection and image optimization for interventional procedures.

How do I handle a nondiagnostic sample in a patient where neoplasia is strongly suspected?

Repeat the aspiration with a larger gauge needle, typically 22 G instead of 25 G, and target the most cellular-appearing region based on ultrasound appearance. Consider a needle core biopsy if cytology remains nondiagnostic, as histopathology may provide a definitive diagnosis when cytology fails. In the bone lesion study by Samii et al., five of 23 patients had nondiagnostic aspirates despite confirmed neoplasia, demonstrating that a negative result does not exclude malignancy. If repeat sampling is still nondiagnostic, discuss surgical biopsy or referral with the owner. Document the sampling limitations in the medical record and recommend staging regardless of the cytologic result.

What cytologic preparation is best for fluid from a cystic or cavitated lesion?

Always prepare both direct smears and a concentrated preparation. Centrifuge an aliquot and smear the sediment for cellular evaluation. For fluid that is grossly turbid or bloody, prepare a direct smear first to assess cellularity before centrifugation. Measure and record the fluid volume, color, and turbidity. Submit a separate sterile sample for culture if the fluid appears purulent or if infection is suspected. The pancreatic pseudocyst series by VanEnkevort et al. reported that aspirated fluid was aseptic in all six patients, but culture remains prudent when clinical signs suggest sepsis. Refrigerate fluid if analysis is delayed beyond one hour.

How should I document the procedure in the medical record?

Record the indication, patient positioning, sedation or anesthesia used, probe frequency, needle gauge and length, number of passes, target site, and whether real-time guidance was used throughout. Describe the lesion's location, dimensions, echogenicity, and vascularity before sampling. Note any complications, including hemorrhage, pneumothorax, or patient deterioration, and the corrective action taken. Include a statement about sample quality and how the sample was handled, such as smears prepared, fluid submitted, or culture requested. AVMA practice resources emphasize that procedure documentation supports continuity of care and medicolegal defensibility. Attach representative ultrasound images to the record where possible.

How do I explain the procedure and its limitations to an owner who is anxious about cost?

Be direct about the purpose: cytology provides a rapid, minimally invasive preliminary diagnosis that guides further testing or treatment. State the expected cost range for the procedure, sedation, and cytology interpretation, and note that a definitive diagnosis may require histopathology if cytology is inconclusive. Explain that the procedure carries a small risk of hemorrhage or needle tract seeding, though these are uncommon. Offer a staged approach, such as cytology first with histopathology only if needed, to manage costs. The MSD Veterinary Manual provides client-facing summaries of diagnostic procedures that can supplement your explanation. Avoid promising a diagnosis, and frame the procedure as one step in a diagnostic plan.

Related Clinical & Scientific Guides

• MRI Monitoring of Brain Tumor Response to Therapy in Dogs
• Ultrasound-Guided Drainage of Abscesses in Small Animals
• Radiographic Monitoring of Total Hip Replacement in Dogs

References and Further Reading

• Endoscopic ultrasound-guided fine needle aspiration training: evaluation of a new porcine lymphadenopathy model for in vivo hands-on teaching and training, and review of the literature.. 2013.
• Safety and correlation of test results of combined ultrasound-guided fine-needle aspiration and needle core biopsy of the canine spleen.. 2011.
• Ultrasound-guided fine-needle aspiration biopsy of bone lesions: a preliminary report.. 1999.
• Ultrasonography of canine gastric epithelial neoplasia.. 1998.
• Pancreatic pseudocysts in 4 dogs and 2 cats: ultrasonographic and clinicopathologic findings.. 1999.
• Learning curve for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic lesions in a novel ex-vivo simulation model.. 2016.
• American College of Veterinary Radiology Resources. American College of Veterinary Radiology.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.

Related Articles

• Ultrasound-Guided Aspiration of Cystic Lesions in Small Animals
• Ultrasound-Guided Abdominocentesis for Therapeutic Paracentesis in Small Animals
• Ultrasound-Guided Drainage of Abscesses in Small Animals
• Ultrasound-Guided Interventional Procedures for Treatment in Small Animals
• Ultrasound-Guided Cystocentesis for Therapeutic Drainage in Dogs and Cats

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.