
Overview
This module describes how to perform a fine needle aspiration biopsy (FNAB), a minimally invasive technique used to obtain samples for cytological investigations.
Indications
Cytological examination of tissues such as:
- Thyroid nodules
- Breast masses
- Suspicious lymph nodes
- Suspicious skin masses
Contraindications
When cytological diagnosis would not alter management
When biopsy could introduce infection into a sterile space
Suspected paraganglioma, hydatid cyst, or vascular neoplasms
When a
safe windowsafe windowLesions < 1 cm in diameter or when other structures are in the way.
for biopsy is not assured (consider ultrasound guidance)
Weigh up risks and benefits in patients with coagulopathy
Patient information & consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“I need to collect some cells from the mass to see what it is and how to manage it. I’m going to use a needle and syringe to withdraw these cells and put them onit on a slide so that the laboratory can examine it under a microscope.”
What can my patient expect?
“You may feel a sharp sting when I insert the needle. The test results can take a few days to come out.”
What is my patient’s role?
“Let me know if you have any allergies or a bleeding tendency, or use blood thinners. Fearing blood or needles is normal, but tell me if you have fainted from it. Keep as still as possible. Afterwards, press firmly on the area to prevent bleeding.”
Preparation
Prepare a trolley with equipment. Using the pencil, write the patient's name and folder number on the
bottom frosted part of the slide
Do not place a sticker over the underside of the slide lengthways as this will make viewing the contents of the slide very difficult. If you cannot find a pencil, use a sticker and write the patient's details on this and stick this on the bottom frosted section of the slide
.

Documentation
Patient labels
Cytology forms
Equipment
Non-sterile gloves
Alcohol-based hand rub
- Sharps containerSharps container
If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.
Alcohol swab
10 ml syringe
Needle, 22G or smaller
A pencil
At least 4 microscopy slides and slide case
Cytological fixative spray
Cotton wool and a plaster
Site and Positioning
The patient should be positioned reclining or supine, with the lesion within easy reach.
Procedure
Follow medical asepsis with non-sterile gloves.
Perform hand hygiene and don gloves.
Assemble the syringe and needle.
Clean the overlying skin with an alcohol swab and allow it to dry.
Stabilise the mass with your non-dominant hand and insert the needle. Once you have penetrated the skin, start to maintain a 1-2 ml suction on the syringe.
Make a few back-and-forth stabbing motions with the needle keeping the tip below the skin surface, until aspirated material appears in the hub of the needle. Do this in in more than one plane.
Stop aspirating; then withdraw.
Ask the patient to apply gentle pressure with cotton wool to the site.
Disconnect the needle, fill the syringe with air, and reconnect the same needle.
Touching the needle tip to the surface of a glass slide, expel the air and aspirated material onto the slide.
Place the second slide face-down on the first and slide them apart to leave an even smear of material on both slides.
Spray one slide with fixative from about 30 cm until it is wet; allow to dry. Allow the second slide to air dry.
Repeat steps 4-12 at least once more to yield a total of at least 4 slides.
Apply a transparent film dressing over the cotton wool.
Dispose of medical waste safely.
Place the slides in the slide case.
Fill in the
cytology formcytology formFill as much detail as possible on this form. Use the barcode stickers on the form and place one in the patient's notes and one on the slide case.
and send the sample to the laboratory. Record the completion of the procedure in patient notes.
Troubleshooting
The sample is only blood.
Remove the needle and apply pressure for a minute. Try again using a smaller needle and a different angle if possible. If still bloody, do fine needle capillary sampling; it is performed in the same manner, but without aspiration. If still bloody, consider a
vascular lesion
Such as Kaposi’s sarcoma or haemangioma
. Note this on the cytology request form.
I punctured a cyst—the aspirate is just fluid.
Empty the cyst and send all the fluid to the lab in a specimen jar for cytology. Perform fine needle aspiration of the remaining mass or the cyst wall.
I don’t have a slide case.
Place the slides in a urine sample container. Place a second container to cover the slide end sticking out, then tape them together.
Risks
Local hematoma, pain, or excessive bleeding at the site
Injury to local structures
Infection at the site
Sharps injury to healthcare personnel
Vasovagal response (fainting)
References
Wright CA. Fine-needle aspiration biopsy of lymph nodes. Continuing Medical Education. 2012;30(2):56-60. Available at: http://www.cmej.org.za/index.php/cmej/article/view/2333/2189.
Sigmon DF, Fatima S. Fine Needle Aspiration. [Updated 2021 Apr 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available at: https://www.ncbi.nlm.nih.gov/books/NBK557486/.
Van Deventer C, Makinde M. How to do a fine-needle aspiration of a breast cyst or nodule. In: Mash B, Blitz-Lindeque J, eds. South African Family Practice Manual. 2nd ed. Pretoria: Van Schaik Publishers; 2010: 300.