Altered activity in cultured cells caused by contaminants in tubes widely used for blood collection and serum preparation.

Cell culture has been recognized as an extremely sensitive system for measuring the toxicity of various materials. A study was done to determine whether the type of tube used to collect blood or store human serum might affect results in experiments requiring blood drawn into such tubes. In order to test tubes for contaminants that might alter cellular activity, a variety of commercially available tubes used for collection of blood and storage of serum were shaken while containing culture medium with fetal bovine serum. The medium was then applied to 3T3 fibroblasts in culture. Measuring incorporation of tritiated thymidine into DNA in log phase cells as an index of cellular proliferation, it was found that medium containing serum preincubated in tubes routinely used for blood collection could be extremely toxic. The same types of tube were also used to prepare human serum. When serum from some of the tubes was applied to 3T3 fibroblasts, a stimulatory effect was observed, perhaps caused by selective adsorption of inhibitory components of the blood or serum by various tubes. It is, therefore, crucial in a properly controlled experiment using serum in vitro to collect blood in tubes that exert no toxic or stimulatory effects in the assay or, at least, to be consistent in one's choice of tube. None of the tubes used for storage of serum showed significant effects in our assay.