Why FNA technique still shapes diagnostic yield in practice
Bottom line
A new Veterinary Practice News feature, “The art of the aspirate,” puts the spotlight on a basic skill that can make or break in-house cytology: fine-needle aspiration, or FNA. The piece argues that technique matters at every step, from choosing aspiration versus nonaspiration collection to making a thin, intact smear and avoiding blood contamination or cell rupture. That emphasis aligns with broader veterinary cytology guidance from Merck Veterinary Manual and Today’s Veterinary Practice, which note that diagnostic yield depends heavily on sample collection, slide preparation, rapid air-drying, and avoiding excessive suction or pressure during smear prep. (merckvetmanual.com)
Why it matters: For veterinary professionals, this is a reminder that many “nondiagnostic” cytology results start in the preanalytic phase, before a pathologist ever sees the slide. ASVCP quality guidance has highlighted the preanalytical phase as a major source of lab error, and clinical cytology references consistently warn that prolonged suction, poor lesion targeting, inadequate redirection, and aggressive slide handling can all reduce cellularity or damage cells. In practice, better FNA technique can improve same-day decision-making, reduce repeat sampling, and help clinics get more value from in-house microscopy or telecytology workflows. (onlinelibrary.wiley.com)
What to watch: Expect continued attention on cytology quality training, especially as more practices lean on digital cytology and faster turnaround models. (pubmed.ncbi.nlm.nih.gov)
Key facts
- Topic
- Fine-needle aspiration (FNA)
- Main point
- Diagnostic success depends on disciplined technique at every step
- Key skills
- Perform the aspirate, prepare quality slides, and recognize common errors
- Sample goal
- High cell harvest with minimal blood contamination and minimal artifact
- Slide prep
- Spread the sample into a monolayer without added pressure
- Timing
- Prepare slides immediately, before material dries or clots in the needle
- Technique selection
- Nonaspiration may be best for highly exfoliative and vascular tissues; aspiration may be needed for firmer or poorly exfoliative lesions
- Common errors
- Prolonged suction, poor localization, fewer than four redirections, and overly forceful squash prep
- Workflow impact
- Better FNA technique can reduce repeat sampling and improve same-day decision-making
A Veterinary Practice News article titled “The art of the aspirate” is making a familiar but important point for clinicians: FNA is simple in concept, but diagnostic success depends on disciplined technique. The article centers on three linked skills, performing the aspirate, preparing quality slides, and recognizing common errors, all of which can materially improve the odds of getting a diagnostic sample. That message is consistent with current veterinary cytology references, which describe sample collection and smear preparation as core determinants of whether cytology will answer the clinical question. (merckvetmanual.com)
The background here is that FNA remains one of the most accessible diagnostic tools in small animal practice. It’s fast, low-cost, minimally invasive, and often possible without sedation, making it a first-line step for many cutaneous, subcutaneous, and nodal lesions. But it also has well-known limitations: some lesions exfoliate poorly, some samples are diluted by blood, and cytology cannot replace histopathology when tissue architecture, grading, or margins are required. Recent reference material from Axiom Veterinary Laboratories and Merck underscores that even well-collected aspirates can still be nondiagnostic, particularly in heterogeneous or mesenchymal lesions. (axiomvetlab.com)
The technical details matter. Merck advises that the goal of FNA is a high cell harvest with minimal blood contamination and minimal artifact. It notes that suction should be released before the needle is withdrawn, because maintaining negative pressure can pull material into the syringe barrel and rupture cells. It also recommends gently expressing the sample onto a clean, dry slide and spreading it into a monolayer without added pressure. Today’s Veterinary Practice similarly advises clinicians to prepare slides immediately, before material dries or clots in the needle, and to leave some slides unstained if they may be submitted for pathologist review. (merckvetmanual.com)
Other practical guidance adds nuance around technique selection. Clinician-focused commentary in Clinician’s Brief says highly exfoliative and vascular tissues, including many lymph nodes and round cell lesions, are often best sampled first with a nonaspiration technique, while firmer or poorly exfoliative lesions may need aspiration. That same source lists common causes of nondiagnostic samples: prolonged suction, failure to release pressure before withdrawal, timid collection, poor localization, fewer than four redirections, and overly forceful “squash prep” slide handling. Needle choice also matters, with 22- to 25-gauge needles commonly recommended depending on tissue consistency. (cliniciansbrief.com)
There’s also a broader quality story behind the article. ASVCP guidance has emphasized that preanalytical factors are a major source of error in veterinary clinical pathology, and a newer PubMed-indexed report on digital cytopathology quality guidelines suggests that as digital review expands, the old problem of poor slides doesn’t disappear, it just moves upstream. In other words, telecytology and digital workflows can speed interpretation, but they still depend on the clinic producing well-collected, well-prepared specimens. (onlinelibrary.wiley.com)
Why it matters: For general practitioners, ER teams, and technicians involved in sample collection, “the art of the aspirate” is really about controlling the part of the diagnostic chain that happens in the exam room. Better FNA technique can mean fewer repeat pokes, fewer inconclusive reports, and faster triage of masses, lymph nodes, and inflammatory lesions. It also supports better communication with pet parents, because clinicians are more likely to have actionable preliminary information the same day, while still recognizing when cytology has reached its limits and histopathology is needed. (axiomvetlab.com)
For practices investing in in-house microscopy, reference lab partnerships, or digital cytology, the operational takeaway is straightforward: training on collection and slide prep may deliver as much value as the interpretation platform itself. The underlying literature and guidance repeatedly point to the same bottleneck, specimen quality. In that sense, the Veterinary Practice News article lands on an issue that is both clinical and workflow-related. (onlinelibrary.wiley.com)
What to watch: The next step is likely more emphasis on standardized cytology training, slide-prep protocols, and digital quality guidelines as practices try to improve diagnostic yield without adding major cost or delay. (pubmed.ncbi.nlm.nih.gov)