In accordance with GOST R ISO 15189–2015 ‘Medical laboratories. Particular requirements for quality and competence’ for the report on the values of the measured value in the patient’s samples, the laboratory must determine and use the measurement uncertainty in the analytical phase. The article discusses in detail the differences between the general analytical error and measurement uncertainty. The authors have tested a typical algorithm for estimating measurement uncertainty. Mandatory conditions and an algorithm for calculating measurement uncertainty (at the analytical stage) in medical laboratories using quantitative immunochemiluminescence analysis are presented.

   Establishing the true causes of thrombocytopenia is of paramount importance, since the tactics of managing patients depend on it. Obtaining information about the activity of thrombocytopoiesis until recently was possible only after examining the bone marrow, but modern laboratory diagnostic capabilities make it possible to evaluate thrombocytopoiesis by a comprehensive clinical blood test performed on a hematological analyzer using a fluorescent optical method (PLT-F). At the same time, in addition to the number of platelets in peripheral blood, information is available on the number of immature platelets (IPF) in absolute and relative terms.

   Objective: to evaluate the possibility of using the PLT-F channel and IPF parameters in the differential diagnosis of thrombocytopenia.

   We reviewed three clinical cases with different pathogenetic variants of thrombocytopenia (immune thrombocytopenia, thrombocytopenia in DIC and thrombocytopenia associated with bone marrow damage). In all cases, a clinical blood test was performed on a Sysmex XN 1000 hematological analyzer using the PLT-F channel. When using the PLT-F channel, parameters are available to differentiate thrombocytopenia according to the mechanism of pathogenesis. The absolute value of IPF is a criterion for the activity of thrombocytopoiesis in the bone marrow, while the relative value of IPF, namely the increase in this parameter, is a criterion for the loss of platelets in the peripheral bloodstream (destruction or increased consumption of platelets). The availability of obtaining diagnostic information about the activity of thrombocytopoiesis and loss of platelets in the peripheral bloodstream using a clinical blood test using the PLT-F channel on Sysmex XN hematological analyzers is of great clinical importance, since a clinical blood test, being a routine study, does not require special conditions for sampling biomaterial, and can be performed not only at the stage of diagnosis, but also during therapy monitoring.

   The study of dynamics of laboratory markers before and after heart surgery makes it possible to predict the risks of postoperative complications. Troponin I is ‘the gold standard’ for diagnosing acute myocardial infarction, but with an increase in the marker after heart surgery, the interpretation of the results can be difficult. Therefore, the search for new combinations of laboratory markers can help in assessing the degree of myocardial damage after surgery, as well as the risk of complications. Myeloperoxidase as a new laboratory indicator is of interest, since there are many studies on the prognostic value of an increase in this marker in patients with coronary heart disease in the development of cardiovascular complications. In the present study, the dynamics of myeloperoxidase, troponin I, and C-reactive protein in patients (n = 60) with a confirmed diagnosis of coronary heart disease before and after elective coronary artery bypass grafting under cardiopulmonary bypass was assessed. The following results were obtained: an increased level of myeloperoxidase in blood plasma in patients before surgery is an additional indicator in assessing the risk of postoperative complications, regardless of the concentration of C-reactive protein. A correlation was found between the concentration of troponin I and the level of myeloperoxidase in the blood, as well as between the duration of cardiopulmonary bypass and the level of MPO 24 hours after surgery.

   This paper presents the results of an expert analysis of laboratory data of patients with pathology of the musculoskeletal system, obtained using an expert analytical system. The personal data of patients who had the index of N-telopeptide of type I collagen molecules (TP1NP) were analyzed. The complex of TP1NP connections in personal observations was established by comparing the structural features of the formation of a panel of ratios of indicators of water-electrolyte metabolism against the background of the dynamics of the analyzed osteomarkers. At the same time, two types of influence of TP1NP growth on the ‘final’ structure of the panel of electrolyte ratios were singled out from the general array and personally analyzed – a high influence of the complex of TP1NP-associated bonds at the intersystem level and at absolute values of TP1NP that go beyond > M + G. A detailed analysis of the recorded relationships is presented with the substantiation of the leading mechanisms for the formation of TP1NP-associated complexes using literary sources. The authors come to the conclusion that under conditions of ‘disturbing’ effects on the body, a pronounced reaction can be achieved, in particular, due to mutual multiplication (multiplication) of the effectiveness of various mechanisms without pronounced shifts in the absolute values of the analyzed indicator. At the same time, the increase in the quantitative indicator of TP1NP with a weak expression of its effect on the final structure of the panel of electrolyte ratios may correspond to the predominant effect on bone metabolism of other factors that go beyond the osteomarkers analyzed in the article, thereby determining the need to continue the search and deciphering different complexes. At the same time, the observations presented and analyzed in this work, which demonstrate a high degree of influence on the integral PSE of the TP1NP-associated complex, can be entered into the archive of the knowledge base and recognized in the routine interpretation of the obtained laboratory data on water-electrolyte metabolism.

   Objective. Determination of the significance of cytological methods in the diagnosis of non-tumor lesions and endometrial tumors.
   Materials and Methods. 69 patients who underwent surgical treatment of hysterectomy or hysteroscopy with separate diagnostic scraping of the cervical mucosa and uterine cavity. The endometrial surface was scraped by Cytobrush. Part of the material was applied to a slide for conventional cytology (CC); the remaining material was placed into the vial for liquid-based cytology (LBC). The results were analyzed using SPSS Statistical Package (SPSS: An IBM Company).
   Results. Histological examination of biopsy material revealed endometrial hyperplasia without atypia (20), atypical hyperplasia (2) and adenocarcinoma (11). The sensitivity of CC and LBC for hyperplasia without atypia was estimated at 100 %, the specificity at 88 % and 94 %, respectively; the positive predictive value at 77 % and 87 %, respectively, and the negative predictive value at 100 %. The sensitivity of CC and LBC for atypical hyperplasia and adenocarcinoma was estimated at 100 %, specificity at 96 %; positive predictive value at 87 % and negative predictive value at 100 %.
   Conclusions. Exfoliative cytology of material from the uterine cavity can be used as an informative method for detecting endometrial cancer and hyperplasia.

   Aim. Study of annexin V levels and cytokine status in patients with acute myocardial infarction.
   Materials and methods. We examined 27 patients with Q-forming myocardial infarction who were admitted 12–24 hours after the development of the clinic, and 20 individuals in the control group. The lipid spectrum was determined using an automatic analyzer Humalizer-3000 (Human, Germany). Immunological studies were performed on a flow cytofluorimeter Navios (Beckman Coulter, USA). Lymphocyte subpopulations were evaluated using monoclonal antibodies produced by Immunotech (Coulter Corporation, USA). A set of ANNEXIN V-FITC/7 AAD (Beckman Coulter, USA) was used to isolate cells that had undergone apoptosis. Isolation of peripheral blood mononuclears was performed by centrifugation on a density gradient Ficol-hypac (Pharmacia Fine Chemicals, Sweden), interleukin-1β was determined using the Vector-Best test system (Vector-Best, Russia), and the tumor necrosis factor was determined using the RayBio Human TNF-alpha ELISA Kit (USA). Statistical data processing was performed using the program package Statistica 10.0.
   Results. In patients with acute myocardial infarction on the background of dyslipidemia (total cholesterol and LDL cholesterol increased, cholesterol-HDL reduced) showed a significant decrease in the total number of T-lymphocytes (СD 3+) (p < 0.05), T-suppressor (СD 8+) (p < 0.01), B-cells number (СD 19+) and the ratio of CD 4+/CD 8+ lymphocytes increased (p < 0.05). In patients with myocardial infarction there was a significant increase of apoptotic cells and рro-inflammatory cytokines involved in apoptosis (IL-1β and TNF-α) in the blood compared with the control.
   Conclusion. Increased spontaneous apoptosis of peripheral blood lymphocytes in patients with acute myocardial infarction indicates the systemic nature of apoptosis in acute coronary pathology, due to increased annexin-dependent apoptosis of T-lymphocytes as a result of immune disorders, which leads to activation of the cytokine system with an increased concentration of рro-inflammatory mediators (TNF-α, IL-1β). The identified dependencies require further study with the prospect of developing predictive algorithms for myocardial infarction outcomes based on indicators of annexin V and pro-inflammatory cytokines.

   This review presents the features of coagulopathy and thrombotic risk in COVID-19 in middle-aged people. A consistent increase in the D-dimer and the presence of thrombosis and PE in seriously ill middle-aged patients with COVID-19 was shown with a decrease in other blood clotting parameters, such as fibrinogen, platelets or antithrombin, which are associated with DIC syndrome. Therefore, there is a need to identify an increased risk of thrombotic events at an early stage and prevent thrombotic events and organ damage as much as possible. The use of thrombolytic therapy is also being considered. Currently, great efforts are being made by the international medical and scientific communities, the new coronovirus infection COVID-19 is a problem and the prognosis for hospitalized patients with COVID-19, especially in the critical form, continues to be unfavorable not only for elderly and old patients, but also for middle-aged patients. age. Despite the fact that this disease is considered multifactorial, thrombotic complications play an important role in the further prognosis in this category of patients.

   Currently, the use of hematological analyzers makes it possible to quickly and accurately count the number of platelets in the vast majority of blood samples. In some cases, the automatic determination of this indicator may be incorrect, due to the limitations of the methods used. Monitoring the results of automatic platelet count is necessary when obtaining pathological values and is carried out by microscopic examination of a peripheral blood smear. The article describes the methods and limitations of automatic determination of the number of platelets, possible causes of erroneous counting and ways to correct the result. Morphological descriptions of the most common artifacts that affect the correct definition of this indicator are presented. Modern methodological approaches to solving the problem of correct platelet counting in EDTA-dependent pseudothrombocytopenia are highlighted.

   The review considers questions about the place of laboratory diagnostics in preventive medicine, in particular, about the possibilities of using laboratory methods in controlling the vaccination of infections with an aerosol transmission mechanism (measles, rubella, mumps, chickenpox, influenza, pneumococcal infection, pertussis, diphtheria, COVID-19). The article highlights the main laboratory methods of seromonitoring (enzyme immunoassay, radial hemolysis reaction in gel, dot-immunoassay, antibody avidity determination, hemagglutination inhibition reaction, microneutralization reaction, FAMA, plaque suppression reaction), their advantages and disadvantages. Also presented a block of data on alternative biomarkers (enzymes, lipids, trace elements, hormones, etc.). which serve as potential predictors of vaccination efficacy. The search for new biomarkers of the effectiveness of the formation of post-vaccination immunity opens up new possibilities for predicting the effectiveness of vaccination, which makes their study a promising direction in the field of vaccinology and laboratory immunology.

   Periodontitis is a multifactorial inflammatory chronic disease initiated by dysbiosis of the commensal microbiota of the oral cavity. With the advent of the multi-ohm approach, which creates datasets with multiple features, machine learning algorithms have become an important technique in translational research. The most effective methods for identifying highly specific interactions of biomarkers with clinical parameters and their implementation in interpretable accurate clinical diagnoses are machine learning algorithms.

   The aim of the study was to evaluate laboratory diagnostic indicators that are significant for predicting the severity of periodontitis using machine learning models.

   We examined 133 patients aged 22 to 73 years with a diagnosis of chronic periodontitis, as well as 53 people without periodontal pathology. After the examination and assessment of the condition of the periodontium of patients, a biological sample of the periodontal fluid was taken. Real-time PCR was used to evaluate periodontopathogenic microflora and mRNA of pro-inflammatory cytokines. Cells of innate and acquired immunity were evaluated in mixed saliva. Machine learning was performed using logistic regression algorithms, naive Bayes classifier, ‘the Random Forest’ with 25 % training. When trained to 25 %, the naive Bayes classifier showed an accuracy of 23 %, logistic regression – 29 %. ‘The Random Forest’ showed 100 % accuracy and selected the following biomarkers associated with periodontitis severity: Porphyromonas endodontalis; CD 3+, CD 14+, CD 19+5–B 27+ cells; mRNA IL-1β, IL-10, IL-18, GATA3, TNFa, TLR 4. In chronic periodontitis, there is a relationship between local indicators of the immune-inflammatory process, such as mRNA of pro-inflammatory cytokines, cells of the immune system, and the severity of pathology. In the analysis of a multifactorial disease such as chronic periodontitis, a machine learning model optimized for a large heterogeneous data set with a large patient sample should be used.