Insidious test tubes
Canadian scientists have found the cause of distortions in the results of laboratory testsEkaterina Lyulchak, RBC daily
The results of the analyses obtained in modern biomedical laboratories equipped with the latest technology are unlikely to cause anyone doubts. Diagnostic doctors do not stop repeating that the probability of error is zero, because the tests are carried out in sterile conditions using disposable syringes and test tubes. However, recently Canadian scientists have exposed the myth of the absolute reliability of laboratory tests and questioned the results of many biochemical studies conducted in recent years. Biochemist Andrew Holt and his colleagues from the University of Alberta have discovered that plastic tubes used to collect and store biological material can block some natural biological reactions, which leads to a distortion of the results of the study.
Experts have found that toxic substances released by plastic can, for example, weaken the effect of drugs. As a result, the analysis data, for example, for the presence of a patient's allergy to a medical drug, will be distorted and the person will take the medicine without even knowing that it is contraindicated to him.
"Laboratory staff work with substances whose mass fraction in the human body is calculated in micrograms. And now imagine that at least a milligram of cleaning agent got into a test tube with the material. That's it. The results of the study will be irreparably distorted, and hence the diagnosis. So the problem associated with the distortion of the results due to the influence of plastic test tubes on the biological material is very acute for doctors, - says RBC daily Doctor of Medical Sciences, Professor, head of the laboratory of hormonal analysis of the Endocrinological Research Center of the Russian Academy of Medical Sciences Nikolay Goncharov. – And due to the fact that not only large and proven companies, but also artisanal firms are engaged in the production of instruments for the laboratory, it is impossible to insure against the fact that the test tubes will contaminate the serum with chemicals. Such a situation is simply unacceptable."
By the way, the lack of plastic test tubes was discovered by accident. Studying the enzyme monamine oxidase, which is responsible for the metabolism of hormones and the destruction of dangerous biologically active substances, Holt and his colleagues constantly received different data. After making sure that all the devices were in good working order, biochemists suspected laboratory test tubes of distorting the results. And, after testing several plastic containers, they found that the substances present on the walls of the test tubes block the activity of the MAO enzyme by 40%. It turned out that on the inside of the plastic flask there were traces of an antimicrobial substance and a water-repellent chemical, which the manufacturer intentionally added to the plastic. The oleamide released by the test tube – a lubricant of organic origin, which is used in the production of plastic tableware – inhibited the activity of the enzyme, contributing to the distortion of the results. In addition, by interacting with nerve cells and cells of the immune system, oleamide, according to experts, has spoiled a lot of research concerning immunity and the nervous system.
However, not everything is so clear. "If the test tubes are made of high–quality plastic and in compliance with all technological standards, no foreign toxic agents will be released into the analysis," Nikolai Adrianov, Candidate of Medical Sciences, Associate professor of the Department of Biochemistry of the Russian State Medical University, told RBC daily. – However, in any mass production there are fakes, because of which some indicators may differ from the correct ones by dozens of times! So if the tests show a multiple increase or decrease in biochemical parameters, it is necessary to reanalyze in another laboratory."
Meanwhile, scientists have discovered that not only test tubes, but also other medical instruments made of plastic can affect biochemical parameters. Pipettes and syringes, just like test tubes, can suppress the activity of enzymes, but plastic cups, on the contrary, enhance the activity of proteins and, in particular, the MAO enzyme that interested scientists. Therefore, it is not surprising that the results obtained were distorted throughout the entire research cycle. This revelation made scientists think that perhaps many of the problems faced by geneticists and microbiologists when growing cell cultures in the laboratory are due to the influence of the test tube material. And although reputable manufacturers of laboratory instruments are sure that the scientist's remarks concern only unscrupulous companies, Andrew Holt thoroughly rinses syringes and test tubes before each experiment, just in case.
Portal "Eternal youth" http://www.vechnayamolodost.ru
18.11.2008