Capillary sample

What is a Capillary Sample?

A capillary sample, also known as a capillary blood sample, is a type of blood sample extracted from the fingertip using a small needle. This method of sampling has a variety of different names, including a “prick” or “finger punch.” The sample of blood extracted is very small, typically around one to two drops - hence the name “capillary” which comes from the Latin for “ tiny vessels”.

Preparation for a Capillary Sample

The capillary sample is taken using a sterilized lancet, and a collection container (such as a finger pad or beveled capillary tube). The area of the fingertip should be sterilized and cleaned just prior to the sampling. During the process, the skin is punctured, and the blood is extracted and collected in the container. The size of the drop can vary depending on the individual’s age and health.

Types of Capillary Samples

There are two main types of capillary samples: venipuncture and finger puncture. Venipuncture is the more commonly used method of collecting a capillary sample. It requires sterilization of the arm or leg and the insertion of a needle into a vein. Finger puncture, on the other hand, usually requires only the sterilization of the fingertip and an antiseptic to clean the area. It is generally the preferred method of collection for use in home testing.

Reasons for Taking a Capillary Sample

Capillary samples are used for a variety of medical purposes, such as:

  • To test for a variety of diseases and disorders
  • To measure blood sugar levels
  • To get a sample for genetic testing
  • To get a sample for paternity tests
  • To measure the concentration of drugs in the system

Risks of a Capillary Sample

The risks of extracting a capillary sample are minimal. However, there is a risk of infection if the area is not properly sterilized prior to the sampling. Additionally, if the lancet is not correctly removed, there is a risk of swelling in the area. If the puncture is deep enough, there is a risk of nerve damage which can result in permanent numbness or pain.

When to Get a Capillary Sample

A capillary sample is typically recommended whenever a doctor wants to analyze a small sample. It is also a good option for those who are unwilling or unable to have a venipuncture, due to fear or medical conditions. While it requires more expertise to conduct than other methods, it is very quick, and the amount of blood extracted is minimal.

Why get a Capillary Sample?

A capillary sample is a valuable tool for many medical processes. It eliminates the need for a full venipuncture and a complicated lab process, which reduces costs. Additionally, the sample can be taken quickly and easily, and doesn’t require a high level of expertise. For medical practitioners and patients alike, the capillary sample is a convenient and low-risk way to collect small, important samples of blood.