Glossary Entry: Capillary Tube


Definition: A capillary tube is a small, narrow tube used in medical practice to collect and analyze blood samples. It is commonly utilized in procedures such as capillary blood sampling and microhematocrit centrifugation.

Detailed Description

Types and Variations

Variations: Capillary tubes come in various sizes, typically ranging from 50-100 mm in length and 1-2 mm in diameter. There are also specialized capillary tubes designed for specific procedures, such as heparinized capillary tubes for anticoagulated blood collection.


Common Uses: Capillary tubes are commonly used for capillary blood sampling in scenarios such as glucose monitoring for diabetic patients, hemoglobin testing, and microhematocrit centrifugation for hematocrit measurement.

Insertion and Placement

Procedure: When using a capillary tube for blood sampling, it is important to ensure proper skin puncture to obtain the sample. The tube is then placed in the blood droplet to collect the required volume, followed by sealing the sample with clay or other suitable material.

Clinical Considerations

Potential Complications

Risks: Complications associated with capillary tube usage include improper skin puncture leading to inadequate blood collection, as well as breakage of the tube causing injury to the patient or healthcare provider.

Care and Maintenance

Maintenance Requirements: Capillary tubes should be handled with care to avoid breakage and contamination. Proper disposal of used tubes is essential to prevent the spread of infectious diseases.

Additional Information

Related Devices

Associated Terms: Lancets, which are used for skin puncture to obtain blood samples for capillary blood sampling, and microhematocrit centrifuges used for hematocrit measurement.

Innovations and Advancements

Recent Developments: Recent advancements in capillary tube technology include the introduction of heparinized capillary tubes and improved quality control measures to ensure accurate blood sample collection.

Regulatory and Safety Notes

Regulations: Capillary tubes used for medical purposes must adhere to regulatory standards and guidelines to ensure patient safety and accurate sample collection.