Pathological examination is performed on cell and tissue specimens from organs in the body biopsied during endoscopy, needle biopsy or surgery. This is considered the gold standard in diagnosing diseases, especially malignant diseases.

Pathology (Histology) or biopsy is a tissue sample taken from a living person for the purpose of diagnosis and treatment. Cytology is another type of material that can be taken from a living person for pathological examination, which is the type of cells present in body fluids (pleural fluid, peritoneal fluid, urine), or naturally exfoliated cells from the covering epithelium (vaginal-cervical epithelium, bronchial epithelium).