# Fine Needle Aspiration Biopsy (FNAB)

## 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

1. Cytological examination of tissues such as:

   1. Thyroid nodules
   2. Breast masses
   3. Suspicious lymph nodes
   4. Suspicious skin masses

## Contraindications

1. When cytological diagnosis would not alter management

2. When biopsy could introduce infection into a sterile space

3. Suspected paraganglioma, hydatid cyst, or vascular neoplasms

4. When a

   safe window
   safe window

   Lesions < 1 cm in diameter or when other structures are in the way.

   for biopsy is not assured (consider ultrasound guidance)

5. Weigh up risks and benefits in patients with coagulopathy

## Patient information and 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

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

1. Patient labels

2. Cytology forms

### Equipment

1. Non-sterile gloves

2. Alcohol-based hand rub

3. Sharps container
   Sharps 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.

4. Alcohol swab

5. 10 ml syringe

6. Needle, 22G or smaller

7. A pencil

8. At least 4 microscopy slides and slide case

9. Cytological fixative spray

10. 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.

1. Perform hand hygiene and don gloves.

2. Assemble the syringe and needle.

3. Clean the overlying skin with an alcohol swab and allow it to dry.

4. 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.

5. 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.

6. Stop aspirating; then withdraw.

7. Ask the patient to apply gentle pressure with cotton wool to the site.

8. Disconnect the needle, fill the syringe with air, and reconnect the same needle.

9. Touching the needle tip to the surface of a glass slide, expel the air and aspirated material onto the slide.

10. Place the second slide face-down on the first and slide them apart to leave an even smear of material on both slides.

11. Spray one slide with fixative from about 30 cm until it is wet; allow to dry. Allow the second slide to air dry.

12. Repeat steps 4-12 at least once more to yield a total of at least 4 slides.

13. Apply a transparent film dressing over the cotton wool.

14. Dispose of medical waste safely.

15. Place the slides in the slide case.

16. Fill in the

    cytology form
    cytology form

    Fill 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

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

1. Local hematoma, pain, or excessive bleeding at the site

2. Injury to local structures

3. Infection at the site

4. Sharps injury to healthcare personnel

5. Vasovagal response (fainting)

## References

1. 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.

2. 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/.

3. 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.