Analysis of thicknesses of blood collection needle by scanning electron microscopy reveals wide heterogeneity

Objectives: The preanalytical phase in clinical laboratory diagnostics is currently receiving more and more attention. This term describes one part of actions and aspects of the "brain-to-brain cycle" of the medical laboratory diagnostic procedure that take place before the analytical phase. However, the preanalytical activities, the handling of unsuitable samples and the reporting procedures are neither fully standardized nor harmonized worldwide. The influence of the properties of the blood collection needle must be acknowledged. In this work, we focused on the investigation of the internal structure and size of standardized 21G blood collection needles. Methods: All parameters were measured with a scanning electron microscope using a Jeol model JSM-6000PLUS. Our. Results: The obtained data shows that the internal surfaces of the needles vary greatly from manufacturer to manufacturer (by around 35 %), and this may play an important role in influencing blood flow and even the risk of blood cell injury (especially hemolysis) during blood drawing. Conclusions: The differential actual needle diameters can vary greatly between needle manufactures and this variety may have a significant impact on laboratory values and may also lead to specimen rejection.