Accurate determination of the amount of blood loss is very important for clinical practice and plays a crucial role in the determination of anesthesia, transfusion tactics and postoperative management period of the patient as a whole. In experimental and military field surgery for this purpose historically and to this day a large number of various methods that are considered in the review of scientific sources is used. The purpose of the study is to consider and analyze the effectiveness of existing methods of determination blood loss. Results. Existing methods for determining the amount of blood loss are divided into direct and indirect. Direct methods are divided into: colorimetric, weight, and volume. Colorimetric method is the Phillips method (1945), based on the ability of copper protein to form a shell around a drop of blood or plasma, which retains its relative density for 10-15 seconds. In 1956 G. A. Barashkov modified the Phillips method by adding hematocrit data. Colorimetric methods make it possible to measure in real time and have a high degree of correlation. Weighing method is gravimetric method, weighing blood-stained surgical material. Historically, the first methods of determining blood loss are considered to be volumetric (direct measurement of the volume of blood lost). Indirect methods are represented by the following groups: clinical, laboratory, hardware, radial, mathematical (calculated), and indicator. Among the clinical methods, the first is the Algover shock index and Buri (1967) (the ratio of heart rate to magnitude systolic blood pressure); visual methods – determination of blood loss by wound size proposed by Grant and Reeve (1951). In shock states monitoring the central hemodynamics on definition of the central venous pressure is applied. To assess capillary perfusion a test of capillary filling is used. Mandatory in clinical practice are laboratory research methods: the content of erythrocytes, hemoglobin, hematocrit, definition of relative blood density. Barashkov's method is based on these indicators. Hardware method is N. M. Shestakov method (1977), a method of determining the circulating blood volume for integral body resistance by using a rheograph. G. A. Shifrin proposed a method based on the registration of the electrical resistance of the body, which is registered when performing bipolar integral rheography. Radiation methods are iodine isotope I131 isotope of chromium Cr-chloride of chromium Cr51Cl3, which is used to determine circulating blood volume; plasma fluorometry method; radionuclide method of circulating blood volume research. Mathematical (calculation) methods involve the use of mathematical formulas to determine the degree of hypovolemia. It is a hematocrit method. F. D. Moore (1956), Nelson's formula is based on hematocrit. In 1983, V. D. Sidora proposed a mathematical calculation method based on the knowledge of circulating blood volume and hematocrit at each body weight in women and men. M. M. Abakumov et al. (2002) proposed a linear regression equation. The amount of blood loss can be calculated by the P. G. Bryusovs formula (1997). M. A. Libov (1962) proposed a formula for determining the amount of blood loss by weighing napkins that are soaked in blood. Indicator method, using Evans blue (blue azo dye T-1824), method of dilution with indocyanine green, as well as the method of determining circulating blood volume using dextar solution (polyglucin). Conclusion. Today, there is no quick enough accurate and cheap method of determining the value of circulating blood volume, despite the growth of technical equipment in medicine. It is vital for practical medicine to have an accurate, fast, cheap and affordable method of determining the amount of blood loss, which will allow timely and accurate calculation of the volume and quality of replacement therapy for blood loss. When providing assistance in areas of mass trauma and emergency surgery, modern medicine is in dire need of a specific system for objective assessment of the severity of victims with blood loss, which will meet the high requirements of practical health care
