Avoiding pre-analytic errors
Achieving adequate capillary blood sample volume
Choosing the right safety lancet for the volume of blood required
- The volume of capillary blood required to perform a test varies, depending on the test type and testing instrumentation
- Safety lancets have varying needle gauges and puncture depths and are designed to produce a range of blood volumes necessary for different tests
- The volume of blood that can be expected from a safety lancet of given gauge and depth specification will vary from patient to patient
- In general, the greater the device needle diameter and puncture depth, the greater the volume of blood produced for testing1
- There are many factors that influence the blood volume produced from any given sampling episode; these include patient hand temperature, safety lancet specification and post-puncture massage technique2
The higher the gauge number, the smaller the needle diameter, and the smaller volume of blood produced for testing*
These materials have been produced in consultation with key opinion leaders and follow global guidelines, but the user should use his or her professional judgement when using any technique or method described in these materials and should take into account all applicable national, regional and institutional guidelines and regulations.
1. Fruhstorfer H, Muller T, Scheer E. Capillary blood sampling: how much pain is necessary? Part 2: Relationship between penetration depth and puncture pain. Prac Diab Int 1995; 12: 184-185. 2. Grady M, Pineau M, Pynes MK, Katz B, Ginsberg B. A Clinical Evaluation of Routine Blood Sampling Practices in patients with Diabetes: Impact on Fingerstick Blood volume and pain. Journal of Diabetes Science and Technology 2014; 8 (4): 691-698.
* For example, a 30-gauge (30G) needle is thinner than a 21-gauge (21G) needle and would, therefore, be used for taking smaller volume blood samples See instruction sheet ‘Collecting a finger capillary blood sample’