I happened upon this article about the effects of blood collection devices and then thought about the effect on the blood as it is being taken. For many people (like my son) it is a really stressful experience. Surely this affects the blood. Not to mention the transport and holding of the blood serum. Just thoughts. (I have to say even looking at the image of a needle can make some people feel a bit scared). I know in the cancer clinic in Bad Salzhausen, one of my friends who has now died (Ira) used to say that his veins ran away every time a nurse would ask for his arm. I have to agree with this assertion. I find my veins hide from being rather protruding veins to very flat ones when I sit in that pathology chair now. I used to search and search in the clinic for a really fabulous nurse who could needle well. A fine art! Everyone at the clinic said that she was the one who could find those vanishing veins.
Blood collection devices interact with blood to alter blood composition, serum, or plasma fractions and in some cases adversely affect laboratory tests. Vascular access devices may release coating substances and exert shear forces that lyse cells. Blood-dissolving tube additives can affect blood constituent stability and analytical systems. Blood tube stoppers, stopper lubricants, tube walls, surfactants, clot activators, and separator gels may add materials, adsorb blood components, or interact with protein and cellular components. Thus, collection devices can be a major source of preanalytical error in laboratory testing. Device manufacturers, laboratory test vendors, and clinical laboratory personnel must understand these interactions as potential sources of error during preanalytical laboratory testing. Although the effects of endogenous blood substances have received attention, the effects of exogenous substances on assay results have not been well described.