Cytology exam: main types and how it is done

The cytology exam is the analysis of body fluids and secretions, through the study of the cells that make up the sample under the microscope, being able to detect the presence of signs of inflammation, infection, bleeding or cancer.

This test is usually indicated to analyze the content of cysts, nodules, unusual liquids that accumulate in body cavities or abnormal secretions such as sputum. Some of the main types of cytology are those performed in the aspiration puncture of thyroid or breast nodules, as well as in the pap smear test or in the aspiration of respiratory secretions, for example.

Although the cytology exam can evaluate various types of changes, it is called oncotic cytology when it specifically searches for the presence of cancer cells.

It should be remembered that cytology and histology are different tests, as cytology evaluates the characteristics of cells present in a material, usually obtained by a puncture, while histology studies entire pieces of tissue, being able to observe the composition and architecture of the material, it is usually collected by biopsy, and is usually more accurate. Check out what the biopsy is and what it is for.

Main types

Some examples of cytology tests are:

1. Aspiration cytology of the thyroid

Thyroid aspiration cytology or fine needle aspiration (FNAB) is a very important test to assess thyroid nodules and cysts, as it is able to indicate whether it is a benign or malignant lesion.

In this examination, the doctor will puncture the nodule, which may be guided by ultrasound, and obtain samples of the cells that comprise it. Then, the material is placed on a slide to be analyzed under a microscope, and it is possible to observe whether the cells have anomalous characteristics that may suggest cancer.

Thus, aspiration cytology is useful to guide the best treatment for a nodule, indicating the need for only follow-up, in benign cases, surgery to remove the thyroid, in suspected cases of malignancy, as well as chemotherapy if identified cancer.

Find out more about when this exam is needed and how to understand the results in Thyroid puncture.

2. Breast aspiration cytology

Aspiration puncture of the breast is one of the most frequent types of cytology and very important for assessing characteristics of breast cysts or nodules, especially when they grow rapidly or show suspicious features of cancer. Understand the risk of breast cyst being cancer.

As with thyroid puncture, the collection of the exam can be guided or not guided by ultrasound, and then the material is sent to the laboratory for the cytology exam to evaluate the cells that make up the aspirated material.

3. Pap smear

In this exam, scrapes and brushing of the cervix are made to collect samples of cells from this region, which will be fixed on a slide and sent to the laboratory.

Thus, this test is able to identify vaginal infections, STDs and signs of cervical cancer. Cancer cell research is also known as oncotic cytology of the cervix, which is a very important test for the early diagnosis and prevention of cervical cancer.

Check out how the Pap test is done and understand the results.

4. Cytology of respiratory secretions

Respiratory secretions such as sputum from the lungs or nasal mucus can be collected, usually by aspiration, to be evaluated in the laboratory. This type of examination is usually requested to try to identify the microorganism that causes an infection, such as fungi or bacteria, such as the tubercle bacillus, for example. In addition, it can also assess the presence of cancer cells, blood or signs of allergy.

5. Cytology of body fluids

Several other types of fluids and fluids in the body can be evaluated in the cytology exam, and a frequent example is urine cytology, when investigating the presence of infections or inflammations of the urinary tract.

Another important example is the cytology of ascitic fluid, which is a fluid that accumulates in the abdominal cavity, mainly due to abdominal diseases, such as cirrhosis. This test may be requested to clarify the cause of ascites, as well as to look for infections or even signs of abdominal cancer. Learn more about this problem in what is ascites.

Fluid that accumulates in the pleura can also be collected for cytology, which is the space between the membranes that line the lungs, in the pericardium, which is the membrane that surrounds the heart, or even the fluid that accumulates in the joints, due to arthritis caused by autoimmune or infectious diseases, for example.