Assess the stability of glucose in different Sampling Systems

Summary Saccharides represent one of the basic building components of all organisms. This group of organic mass is the easiest available and the most ready source of energy. Glucose possesses the basic physiological meaning for the human organism. It is the most rapid source of energy for all body tissues. It represents the only source of energy for brain cells and erythrocytes they cannot do without. The disease called diabetes mellitus originates in the disorder of saccharides metabolism. The increase in diabetes mellitus has become an epidemic recently and a serious civilisation threat of human health as well. The blood glucose estimation is therefore the basic biochemical examination that reflects the topical situation of glucose homeostasis. The blood glucose estimation is meaningful first of all for prevention, diagnostics and long-term follow-up of diabetes patients. The own estimation is performed from the whole blood, serum or plasma, either before or after meals. For the correct interpretation of results it is essential to know that the reference values differ according to the type of material analysed. The patients can measure themselves their blood glucose level by using a glucometer. This is a device serving for the quick but approximate measurement of blood sugar. It works on the principle of evaluating of the electrochemical or photometric signal. In laboratories, the enzyme methods (with hexokinase and glucoseoxidase) or electrochemical methods are mostly used for the glucose estimations. The immense clinical meaning of glucose estimation in the diagnostics of diabetes mellitus is lacking in the field of pre-analysis and stability of glucose in the sample. If the glucose is not estimated immediately after the taking its level decreases. The stability of glucose can be achieved with an immediate immersion of the test-tube with the sample into the drift-ice but this way cannot be applied to the routine practise. That's why the glycolyse inhibitor NaF is used. If a test-tube with a separating gel is used for taking the gel separates the blood elements from serum and glucose presents a higher stability then. The instability of glucose can lead to false diagnostic conclusions. The goal of my study was an estimation of glucose concentration and consideration of its stability in the different sample systems in a group of 50 persons. The original intention was to estimate the glucose concentrations only in two types of test-tubes: with the stabilizer NaF and with the separating gel (this one is mostly used in doctor´s offices), but later on I used the third type of the test-tube for even more object imagination of a (non-)stability in the further type of taking system. I carried out the measurements in 3 time sections: after 1, 6 and 24 h respectively after taking with the help of the most modern laboratory device and then assessed and compared the values in different groups of samples. The glucose levels measured 1 hour after the taking were nearly identical in all 3 types of test-tubes. More significant differences were measured in samples assessed 6 and 24 h after the taking. The greatest decrease of the glucose level was measured in samples taken into test-tubes without separating gel and stabilizer. That´s why blood for glucose estimation should be taken only into the test-tubes with the stabilizer or with separating gel and the centrifugation should be performed soon. The physicians should take into consideration the instability of glucose while evaluating the results and a possible decrease of glycaemia measured value in dependence on the type of taking system and on the interval between taking and processing of the sample