Liquid-based cytology is a method of preparing samples for examination in cytopathology. The sample is collected, normally by a small brush, in the same way as for a conventional smear test, but rather than the smear being transferred directly to a microscope slide, the sample is deposited into a small bottle of preservative liquid. At the laboratory, the liquid is treated to remove other elements such as mucus before a layer of cells is placed on a slide. [1]
For many years, efforts have been made to develop methods that would enhance the sensitivity and specificity of the Papanicolaou smear (also called Pap smear). Emphasis has been placed on creating automated screening machines whose success depends on a representative sampling of cells on standardized slides containing a monolayer of well-stained, well-preserved cells. [2]
From this research and development, liquid-based gynecologic specimen collection has evolved. Its proponents argue that liquid-based preparations outperform conventional smears because of improved fixation, decreased obscuring factors, and standardization of cell transfer. Proponents point out that, in direct smears, the cells are not transferred in a representative fashion and that up to 90% of the material scraped from the cervix may be discarded with the sampling device. With liquid-based collection, the sampling will be representative and operator-dependent variation will not occur since processing is controlled by the laboratory.
SurePath (by BD) and ThinPrep (by Hologic) are two such systems currently approved by the United States Food and Drug Administration (FDA) for cervicovaginal testing. With both methods, the sample is collected in the conventional manner with one of the brush instruments but, instead of being spread onto a glass slide, it is transferred to a vial of transport medium. [3]
The United Kingdom screening programmes changed their cervical screening method from the Pap test to liquid-based cytology in 2008. [4]
Liquid-based cytology improves specimen adequacy. [3]
The most significant alterations seen with the ThinPrep technique include: [5]
As studied on SurePath and ThinPrep, early trials showed increased detection of high-grade cervical intraepithelial neoplasia (CIN2 and CIN3), [6] [7] but subsequent meta-analyses and prospective randomized trials have failed to demonstrate a significant difference between conventional smears and liquid cytology in the detection of CIN2 and CIN3. [8] [9] [10]
The cervix or cervix uteri is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long and roughly cylindrical in shape, which changes during pregnancy. The narrow, central cervical canal runs along its entire length, connecting the uterine cavity and the lumen of the vagina. The opening into the uterus is called the internal os, and the opening into the vagina is called the external os. The lower part of the cervix, known as the vaginal portion of the cervix, bulges into the top of the vagina. The cervix has been documented anatomically since at least the time of Hippocrates, over 2,000 years ago.
The Papanicolaou test is a method of cervical screening used to detect potentially precancerous and cancerous processes in the cervix or, more rarely, anus. Abnormal findings are often followed up by more sensitive diagnostic procedures and, if warranted, interventions that aim to prevent progression to cervical cancer. The test was independently invented in the 1920s by the Greek physician Georgios Papanikolaou and named after him. A simplified version of the test was introduced by the Canadian obstetrician Anna Marion Hilliard in 1957.
Cervical cancer is a cancer arising from the cervix. It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Early on, typically no symptoms are seen. Later symptoms may include abnormal vaginal bleeding, pelvic pain or pain during sexual intercourse. While bleeding after sex may not be serious, it may also indicate the presence of cervical cancer.
Georgios Nikolaou Papanikolaou was a Greek physician, zoologist and microscopist who was a pioneer in cytopathology and early cancer detection, and inventor of the "Pap smear".
Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1928. Cytopathology is generally used on samples of free cells or tissue fragments, in contrast to histopathology, which studies whole tissues. Cytopathology is frequently, less precisely, called "cytology", which means "the study of cells".
Colposcopy is a medical diagnostic procedure to visually examine the cervix as well as the vagina and vulva using a colposcope. Numbing should be requested prior to procedure.
Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology, in cytology, and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses of diseases at the microscopic level. Stains may be used to define biological tissues, cell populations, or organelles within individual cells.
Fine-needle aspiration (FNA) is a diagnostic procedure used to investigate lumps or masses. In this technique, a thin, hollow needle is inserted into the mass for sampling of cells that, after being stained, are examined under a microscope (biopsy). The sampling and biopsy considered together are called fine-needle aspiration biopsy (FNAB) or fine-needle aspiration cytology (FNAC). Fine-needle aspiration biopsies are very safe minor surgical procedures. Often, a major surgical biopsy can be avoided by performing a needle aspiration biopsy instead, eliminating the need for hospitalization. In 1981, the first fine-needle aspiration biopsy in the United States was done at Maimonides Medical Center. Today, this procedure is widely used in the diagnosis of cancer and inflammatory conditions. Fine needle aspiration is generally considered a safe procedure. Complications are infrequent.
Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, is the abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer. More specifically, CIN refers to the potentially precancerous transformation of cells of the cervix.
Papanicolaou stain is a multichromatic (multicolored) cytological staining technique developed by George Papanicolaou in 1942. The Papanicolaou stain is one of the most widely used stains in cytology, where it is used to aid pathologists in making a diagnosis. Although most notable for its use in the detection of cervical cancer in the Pap test or Pap smear, it is also used to stain non-gynecological specimen preparations from a variety of bodily secretions and from small needle biopsies of organs and tissues. Papanicolaou published three formulations of this stain in 1942, 1954, and 1960.
A koilocyte is a squamous epithelial cell that has undergone a number of structural changes, which occur as a result of infection of the cell by human papillomavirus (HPV). Identification of these cells by pathologists can be useful in diagnosing various HPV-associated lesions.
Aurel A. Babeș was a Romanian scientist and one of the discoverers of the vaginal smear as screening test for cervical cancer.
Colin Robert Andrew Laverty was an Australian medical practitioner and was the first to confirm that the human papillomavirus was much more common in the cervix than previously thought and, in 1978, he suggested that this virus be considered as possibly involved in the causation of cervical cancer. He was also a prolific art collector.
An anal Pap smear is the anal counterpart of the cervical Pap smear. It is used for the early detection of anal cancer. Some types of human papillomavirus (HPV) can cause anal cancer. Other HPV types cause anogenital warts. Cigarette smokers, men who have sex with men, individuals with a history of immunosuppression and women with a history of cervical, vaginal and vulval cancer are at increased risk of getting anal cancer. Vaccination against HPV before initial sexual exposure can reduce the risk of anal cancer.
The Bethesda system (TBS), officially called The Bethesda System for Reporting Cervical Cytology, is a system for reporting cervical or vaginal cytologic diagnoses, used for reporting Pap smear results. It was introduced in 1988 and revised in 1991, 2001, and 2014. The name comes from the location of the conference, sponsored by the National Institutes of Health, that established the system.
Cervicography is a diagnostic medical procedure in which a non-physician takes pictures of the cervix and submits them to a physician for interpretation. Other related procedures are speculoscopy and colposcopy. The procedure is considered a screening test for cervical cancer and is complementary to Pap smear. The technique was initially developed by Adolf Stafl, MD, of Medical College of Wisconsin in 1981.
Calcofluor-white or CFW is a fluorescent blue dye used in biology and textiles. It binds to 1-3 beta and 1-4 beta polysaccharides of chitin and cellulose that are present in cell walls on fungi, plants, and algae.
Cervical cancer screening is a medical screening test designed to identify risk of cervical cancer. Cervical screening may involve looking for viral DNA, and/or to identify abnormal, potentially precancerous cells within the cervix as well as cells that have progressed to early stages of cervical cancer. One goal of cervical screening is to allow for intervention and treatment so abnormal lesions can be removed prior to progression to cancer. An additional goal is to decrease mortality from cervical cancer by identifying cancerous lesions in their early stages and providing treatment prior to progression to more invasive disease.
Hashime Murayama (1879–1954) was a Japanese American painter and scientific illustrator. He was best known for his exquisite paintings of birds, insects, fish, mammals, and other wildlife. Employed by the National Geographic Society from 1921 to 1941, his work was featured in The National Geographic Magazine.
Andromachi "Mary" Mavrogeni Papanikolaou was a Greek laboratory technician and the wife of Georgios Papanikolaou, the Greek pathologist who independently invented the pap test. For 21 years, Mary Papanikolaou volunteered to have her cervix sampled and smeared by her husband to help with his efforts to create the pap test, which has been shown to reduce cervical cancer deaths by up to 80 percent.
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