Sampling (medicine)

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Medical equipment used to collect samples from patients

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.

By sampling technique[edit]

  • 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 (cutting out), a surgical method for the removal of solid or soft tissue samples.

Biopsy or cytopathology[edit]

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[edit]

Different types of matter that are sampled can be categorized by solidness versus fluidity, such as:

Body fluid sampling[edit]

Body fluid sampling includes:

By component of interest[edit]

The sampled matter can be analyzed for various components, for example:

Microbiological sampling[edit]

Demonstration of throat swab collection

Microbiological sampling include:

  • Blood sampling for blood cultures, performed similarly as that for tests on the fluid itself above
  • Throat swab for throat culture. It is performed by applying a cotton swab to the surface of the throat.
  • Sampling of sputum from the lungs for sputum culture. It can be performed by special techniques of coughing, or by a protected specimen brush (PSB),[1] 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.


  1. ^ Chastre, J.; Viau, F.; Brun, P.; Pierre, J.; Dauge, M. C.; Bouchama, A.; Akesbi, A.; Gibert, C. (1984). "Prospective evaluation of the protected specimen brush for the diagnosis of pulmonary infections in ventilated patients". The American Review of Respiratory Disease. 130 (5): 924–929. PMID 6497170.