Fine Needle Aspirate in dogs

A fine needle aspirate (FNA) is a simple procedure that helps vets find out what’s inside a lump or swelling on your dog. It’s a safe and relatively inexpensive way to check lumps in dogs of any age, size or breed.

A fine needle aspirate doesn’t involve cutting into the skin. The procedure can often be carried out during a consultation, so your dog won’t even need to stay at the vet practice. Side effects are uncommon and between 70 and 95% of FNA’s provide helpful answers. Vets use the results of a fine needle aspirate to work out the best treatment plan for your dog.

What it’s for

What’s a fine needle aspirate for in dogs?

It’s always worrying when you find a lump on your dog. Lots of swellings look the same. Most are harmless, but some are more serious. It’s impossible to be sure what a lump is just by looking at it. An FNA helps identify the type or cause of a swelling. And from there, decide on the best and safest course of treatment.

When will vets advise an FNA?

Vets may advise an FNA for lumps which are:

New
Growing quickly
Changing size, shape or colour
Becoming painful

Why do we want to know what a lump is?

Peace of mind: confirming whether a lump is innocent by finding out what cells are inside.
Deciding on treatment: using FNA results combined with physical examination for infections, abscesses, blood blisters.
Deciding on surgery: knowing what cells make up the lump helps us decide whether to remove it.
Diagnosing non-cancerous illnesses: liver disease, immune disorders and more.

How it’s done

Fine needle aspirate in dogs: how it’s done

FNA is simple, quick and relatively painless for your dog. It’s just like having an injection, but the vet takes a sample out instead of injecting medicine in! Most dogs don’t need sedation, just the usual vet cuddles!

The vet inserts a fine, sterile needle into the lump and rotates it.
The needle collects a tiny sample of the lump (some cells, fluid, tissue etc) in the barrel
The vet pushes the needle contents out onto a microscope slide using a syringe full of air
The slide is put into special dyes to make cells visible under a microscope
A vet or pathologist examines the slide and identifies any cells present

The vet may examine the sample ‘in-house’ in their own laboratory. You’ll get results within a day or two

Otherwise, the sample goes to a special laboratory for examination. In this case, results take 1-2 weeks, depending on the tests needed.

How to prepare your dog for an FNA

Little preparation is needed for an FNA. Often it is carried out during a consultation (so unplanned). Keeping them as still as possible, with lots of cuddles and a calm reassuring voice is all that’s needed.

Why your dog may need sedation for an FNA

Your dog may need sedation to make the test safer and/or more comfortable for them.

For example:

Relaxing your dog if they don’t like handling (especially not at the vet’s!)
Taking a sample from an awkward location or taking multiple samples.
Performing an FNA with ultrasound guidance. This allows a vet to carefully place the needle in the correct location to collect a sample from deep under the skin or inside the tummy.

Costs

How much does a fine needle aspirate in dogs cost?

FNA is an inexpensive test. It’s quick and straightforward. There aren’t any surgery or hospital fees. Costs vary between practices but could be anywhere between £25 to £200 in practice, depending on:

Whether sedation is required
How many lumps are sampled
Location of the lumps
Whether the sample is examined in-house or sent to a laboratory
Where you live and the type of practice
Whether or not laboratory fees are included

Fees for examination of the sample (cytology) are usually in addition to FNA fees. But always check with your vet first.

Risks

Is a fine needle aspirate safe for my dog?

FNA is a very safe procedure. Risks or complications are rare, but can include:

Bleeding from the sampling site.
Infection: the needle carries skin bacteria through the skin and into the swelling.
Allergic reaction: sampling lumps containing cells called mast cells may trigger an allergic response within 24-48 hours, such as swelling, redness and discomfort. If your vet suspects a mast cell tumour, they may give your dog an antihistamine injection before the FNA.

Call a vet if you notice any changes in the lump after an FNA

Recovery tips

Does my dog need special care after an FNA?

FNA is a simple procedure, so we don’t need to worry too much about specific aftercare.

Keep the site clean and wipe away any bleeding or discharge
Bathe gently with warm salt water if discharge is sticky or dried to the skin (1 teaspoon salt to one pint of warm water)
Discourage your dog from licking or scratching the site. Your vet may suggest a cone collar.

When to worry

When to worry after a fine needle aspirate in dogs

Serious complications of FNA are extremely rare. When they happen it’s either due to infection or a severe allergic response called an anaphylactic reaction.

Anaphylactic reactions are life-threatening.

Find your nearest vet immediately if you think your dog is suffering an anaphylactic reaction: