Evaluation of the opportunity of conservation of plasma and blood serum by freezing for the following investigation of vitamins content

The possibility of freezing samples of human plasma and serum at minus 18°C for subsequent research on the content of vitamins has been experimentally proved. Plasma and serum samples of 40 military personnel were examined on the day of blood collection (without freezing) and then compared with the results of the analysis of the same samples that were frozen at minus 18°C after 7, 60 and 120 days of storage. We used the method of simple freezing of plasma and serum samples in the freezer at a temperature of minus 18°C for a period of not more than 120 min after blood collection. Defrosting after storage was carried out passively at room temperature. The content of folic acid, vitamins B1, B2, B12, C, A, D, E wasstudied using high-performance liquid chromatography, immunochemoluminescence, fluorimetric and spectrophotometricmethods. According to the results of the statistical comparison of the content of the studied vitamins in fresh and frozenplasma and serum samples, the absence of significant differences between the samples was established; the deviation from theinitial values did not exceed 1-2% on average. The proposed method of preserving samples of human plasma and serum byfreezing at a temperature of minus 18°C can be used to analyze the content of vitamins in frozen samples, without the use ofcorrection factors. Initially, the technique was tested to organize the study of the vitamin security of military personnel servingin the Arctic zone of the Russian Federation. The practical significance of the study is to offer a convenient and affordablemethod of preserving plasma and serum samples for transportation in frozen form from remote areas, where the laboratorypossibilities of studying the content of vitamins in the blood for therapeutic and prophylactic purposes are limited. Frozensamples are convenient for storage up to 12 days when their immediate laboratory research is impossible.

vitamins, dietary supplements, deficiency, freezing, plasma, serum, laboratory diagnostics