He FNAC (Fine Needle Aspiration Cytology) test is a diagnostic procedure used to obtain a sample of cells from a lump or mass in the body. It involves using a thin needle to extract cells from the affected area, which are then examined under a microscope to determine whether they are cancerous or non-cancerous, particularly those of the breast, thyroid, lung, and lymph nodes. It can also be used to diagnose non-cancerous conditions, such as infections or cysts.

The advantages of the FNAC test include that it is a minimally invasive procedure, meaning it involves only a small needle, and can often be done in an outpatient setting. Results can be obtained quickly, often within hours, and the procedure is relatively low-cost.

The FNAC test can be used to diagnose a variety of conditions, including:
1. Breast lumps
2. Thyroid nodules
3. Lymph nodes
4. Salivary gland tumors
5. Soft tissue masses