What is Cell Aspiration (FNA)?
Fine needle aspiration (FNA) is a minimally invasive diagnostic procedure used to take a sample of cells from a specific part of the body for laboratory testing. This examination is typically performed by a pathologist or radiologist who punctures the target tissue and a small amount of cells with a thin needle for microscopic analysis. The biggest advantage of FNA is that it is very invasive, does not require incisions, leaves only small pinholes, and has a shorter recovery time compared to traditional surgical biopsies.
Compared to other biopsy methods, FNA has the following advantages:
- Less invasive: Only local anesthesia is required, and in some cases, anesthesia may not be required.
- Quick recovery: Patients can usually resume their daily activities immediately after the examination.
- Low cost: FNA is less expensive than surgical biopsy.
However, FNA also has limitations, such as the small amount of cells extracted, which can increase diagnostic uncertainty. In some cases, if the FNA results are inconclusive, an additional core needle biopsy or surgical biopsy may be required.
In Hong Kong, FNA is widely used for the initial evaluation of thyroid nodules, lymphadenopathy, etc. According to the Hong Kong Health Bureau, around thousands of FNA tests are used every year to diagnose thyroid diseases.
Why do you need to do FNA?
The main purpose of FNA is to help doctors diagnose diseases, especially if there are abnormal lumps or nodules in the patient’s body. Here are some common application scenarios for FNA:
- Thyroid nodules: To assess whether the nodule is benign or malignant.
- Swollen lymph nodes: Determine if the swelling is caused by infection, inflammation, or cancer.
- Breast lumps: distinguish between cysts and solid tumors.
In addition, FNA can be used to diagnose abnormalities in other areas, such as masses in the salivary glands, soft tissues, or internal organs. This allows doctors to quickly obtain cytology reports and develop follow-up treatment plans.
In Hong Kong, FNA is widely used. According to the Hong Kong Cancer Registry, about 30% of thyroid cancer cases are first diagnosed through FNA. This test not only saves time but also reduces unnecessary open surgery.
Preparation before the FNA test
Before undergoing FNA testing, patients should prepare for:
- Tell your doctor about any medications you are taking, especially anticoagulants (such as aspirin or warfarin), as they can increase the risk of bleeding.
- Provide a history of allergies, especially allergic reactions to anesthetics and disinfectants.
- On the day of the examination, try to put on and take off loosely so that the doctor can perform the puncture.
In some cases, your doctor may recommend that you stop taking anticoagulants for a few days to reduce the risk of bleeding during the test. In addition, patients do not need to fast unless the test site involves the abdomen (e.g., liver or pancreas).
It is usually shorter, around 15-30 minutes, but the exact time depends on the test site and the doctor’s experience. Patients must arrive at the clinic or hospital in advance to complete the necessary registration and preparation.
FNA Review Process
FNA tests are usually performed in the radiology or pathology department of a clinic or hospital. Here are the detailed steps to check:
- Disinfection: The doctor cleans the puncture site with an antiseptic solution to reduce the risk of infection.
- Local anesthesia: Your doctor may inject a small amount of local anesthetic into the puncture site if necessary.
- Puncture: A thin needle (usually a 22-25 gauge needle) is used to puncture the target tissue and a sample of the cells is taken.
- Cell collection: The extracted cells are smeared on glass slides or placed in a preservation solution and sent to the pathology laboratory.
The entire procedure usually takes only a few minutes, and patients may experience only mild discomfort or stress. The English name is Fine Needle Aspiration, abbreviated as FNA, and is an internationally accepted medical term.
In Hong Kong, the accuracy of FNA tests is very high, especially when performed by experienced doctors. According to a report by the Hong Kong Medical Journal, the diagnostic accuracy of thyroid FNA can reach more than 90%.
Care after FNA test
After the test, patients may experience the following mild side effects:
- Pain: There may be mild pain at the piercing site, which is usually relieved with over-the-counter pain relievers.
- Bruising: A small number of patients may present with localized bruising, and ice is recommended to reduce swelling.
- Bleeding: In rare cases, mild bleeding occurs and can be stopped by pressing on the puncture site for a few minutes.
If you have any of the following abnormalities, seek medical attention immediately.抽組織化驗
- Persistent pain or swelling at the puncture site.
- Fever or signs of infection (e.g., redness, swelling, suppuration).
- Abnormal bleeding or discharge.
Most patients can return to normal activities immediately after the test, but it is recommended to avoid strenuous exercise for 24 hours to reduce the risk of bleeding.
Interpreting FNA Test Results
FNA reports are usually prepared by a pathologist and may include the following terms:
- Benign: the cells are free of abnormalities and do not require further treatment.
- Malignant: The cells appear cancerous and require further evaluation and treatment.
- Inconclusive: Cell changes may be ambiguous, and FNA or other tests may need to be repeated.
Based on the results, your doctor will recommend a follow-up treatment plan. For example, if the outcome is malignant, surgery, chemotherapy, or radiation therapy may be required. If the results are inconclusive, a core needle biopsy or image tracing may be recommended.
In Hong Kong, the interpretation of FNA results is usually done by a professional pathology team and combined with clinical data for a comprehensive evaluation. The patient should discuss the content of the report in detail with the treating physician to understand its importance and next steps.