In medicine, sampling is gathering of matter from the body to aid in the process of a medical diagnosis and/or evaluation of an indication for treatment, further medical tests or other procedures. In this sense, the sample is the gathered matter, and the sampling tool or sampler is the person or material to collect the sample. Sampling is a prerequisite for many medical tests, but generally not for medical history, physical examination and radiologic tests.
Obtaining excretions or materials that leave the body anyway, such as urine, stool, sputum, or vomitus, by direct collection as they exit. A sample of saliva can also be collected from the mouth.
Excision, a surgical method for the removal of solid or soft tissue samples.
Scraping or swiping. In a Pap test, cells are scraped off a uterine cervix with a special spatula and brush or a special broom device that is inserted through a vagina without having to puncture any tissue. Epithelial cells for DNA testing can be obtained by swiping the inside of a cheek in a mouth with a swab.
In terms of sampling technique, a biopsy generally refers to a preparation where the normal tissue structure is preserved, availing for examination of both individual cells and their organization for the study of histology, while a sample for cytopathology is prepared primarily for the examination of individual cells, not necessarily preserving the tissue structure. Examples of biopsy procedures are bone marrow biopsy, brain biopsy, skin biopsy and liver biopsy.
By sampled matter
Different types of matter that are sampled can be categorized by solidness versus fluidity, such as:
*Capillary blood sampling, generally by using a blood lancet for puncture, followed by sampling by capillary action with a test strip or small pipe. This is common for routine diabetic monitoring for glucose.
*Venous blood sampling, also called phlebotomy. It is generally done by venipuncture. Other than routine diabetic monitoring for glucose, the majority of blood tests are done on samples of venous blood taken by a health professional, which includes phlebotomists which are particularly trained for trained in venipuncture. Such samples are commonly collected in capped test tubes, often with a small amount of some sort of preservative.
Sampling of sputum from the lungs for sputum culture. It can be performed by special techniques of coughing, or by a protected specimen brush, which is a brush that can be retracted into a plastic tube to prevent contamination of bacteria in the throat while inserting and removing the instrument.
