Cytology refers to the study of cells, or cell biology, in terms of their structure, composition, and interaction between one another within their environment in the body. Cytology can also refer to cytopathology, which is the study of cell structure in order to diagnose disease. Cytology became prominent in the 19th century as a way to explain and describe the existence of cells in the body. Cytological procedures look at cells from bodily fluids and lumps on the body, the most well-known of which is a cervical smear (Pap test). Often, they work in a similar way to tissue pathologies.
Cytology focuses on recognising similarities and differences in cells. This is intended to help identify different types of cells, and the way they function in the body. Differences in cells can also contribute to understanding disease. Cytology also examines interaction between cells, as cytologists can predict problems or examine environmental dangers to cells through the study of how cells relate to one another. As humans are multi-cellular animals, deficiencies in one kind of cell and excesses in another can be warning signs of many types of disease. Cytology can therefore examine how the presence of white blood cells in a blood count test correlates to anaemia. Cytology may also lead to the diagnosis of autoimmune disorders through abnormal cell reaction.
Cytopathology can also detect the presence of bacteria or infection through blood and urine analysis. It is also used as a way to detect cancer. The most well known cytology examination is a woman’s yearly cervical examination, which involves taking a sample from the inside of the cervix and analysing the cells to detect the early formation of cancer cells. Similarly, needle biopsies of lumps in the breast or other cites in the body can do the same kind of thing. This kind of preliminary detection can lead to greater survival rates.
In gynaecology, the Papanicolaou test, otherwise known as the Pap smear, Pap test, cervical smear, or smear test, is a method of medical screening designed to detect the early signs of cervical cancer through finding infection or abnormalities in the endocervix and endometrium. Cells are taken from the outer opening of the cervix of the uterus and the endocervix and analysed. If abnormalities require further inspection, the patient may be referred to a colposcopist for a detailed inspection of the area. It was developed by Aurel Babes and Georgios Papanikolaou independently in the early 20th century, and primarily detected hormonal changes in vaginal cells. Later, this was refined with the invention of liquid based cell thin-layer technology.
Fine Needle Aspiration Cytology (FNAC) is a method of biopsy involving an 18 to 27 gauge needle attached to a syringe. This needle is used to pull out cells from lesions or swellings in organs of the body. The cells extracted are then tested for abnormalities in order to detect disease. This procedure is dependent largely on the skill of the practitioner, and therefore results and may vary. This method is poorly developed in the USA, but is used widely in Europe and India.
Liquid cytology is a method that has made Pap smears more reliable. It involves rinsing the cervical samples in a vial of preserving liquid. This liquid is usually ethanol based, called Sure-Path and Thin-Prep, and has the advantage over traditional methods of cervical cell analysis in that it is suitable for low and high risk HPV testing, and increasing satisfactory samples. Proper sample acquisition is important to the accuracy of subsequent tests. Once the samples are in the preserving liquid, an automated machine separates the cells and filters out the blood and mucus. Then, the cells are placed on a slide so they are easy to read.