Educational video for training specialists in clinical laboratory diagnostics.

The adaptation of educational programs under restrictions during the SARS-CoV-2 coronavirus pandemic and after it is based not only on the widespread use of video lectures, but also on the introduction of a number of new educational technologies. Hybrid learning will become the cornerstone of future educational technologies in clinical laboratory diagnostics and will contribute to the creation of virtual practical classes with examples of analysis of laboratory testing results based on case histories (Case Technologies). The key aspect in the implementation of video cases into the educational process is the development of video materials. The use of educational video cases developed by Vector-Best in the process of training specialists in clinical laboratory diagnostics during the cycles «Retraining¼ and «General Improvement¼ at the Department of Clinical Laboratory Diagnostics of the Saratov State Medical University named after V. I. Razumovsky of the Ministry of Health of Russia was a convenient format and received positive assessment of cadets. Currently, the «IVD gallery¼ section has appeared on the FLM website and the placement of an additional educational resource - a library of educational video cases.

[Analysis of urinary stone composition by infrared spectroscopy in the population of the European part of Russia].

INTRODUCTION: Urolithiasis is one of the most common urological diseases, which affect at least 3% of the population. AIM: To study the epidemiology of urolithiasis in the European part of the Russian Federation and to determine the composition of urinary stones in order to understand the pathogenetic mechanisms of urinary stones formation. MATERIALS AND METHODS: Urinary stone were obtained from 2888 patients with urolithiasis and the composition of kidney stones was analyzed using the method of infrared spectroscopy. RESULTS: The predominance of oxalate stones was seen in kidney stones with mixed composition (83%) and the prevalence of uric acid stones (54%) was revealed in "pure" kidney stones. Urinary stones with a predominance of oxalates had significantly less impurities (12,4%) than stones with a predominance of uric acid, phosphates and carbonates with average amount of impurities more than 24%. Conslusion. The analysis of stone composition with a consideration of pathogenic factor showed that disorders of calcium metabolism in the population of the European part of the Russian Federation prevailed (88%).

Helicobacter pylori infection: place of serological and cultural diagnostics in clinical guidelines.

The purpose of this work was to familiarize doctors with the methods and significance of serological and cultural diagnostics of H. pylori infection on the example of the test for diagnosing the state of the gastric mucosa «Gastropanel¼. Blood serum tests were performed for 1057 patients and 122 healthy people aged 18-64 years: pepsinogen I (PG I), pepsinogen II (PG II), gastrin-17 (G-17), basal/stimulated), antibodies (IgGHp) to H. pylori (Biohit Oyj, Finland). The medians of the studied group indicators did not exceed the reference intervals. 398 (34%) patients have negative H. pylori status (IgGHp-). 275 (26%) patients with serum PG I≤70 mcg/ml were identified. The ratio of PG I/II≤3 in 84 (8%), 36 of them (43% of the group PG I/II≤3) - IgGHp-.

Validation of the infrared spectroscopy method for analysis of the composition of urine concretes.

The aim of this study was to validate the method for analyzing the composition of calculus using infrared (IR) spectroscopy by studying model mixtures of salts. Study was made with an ALPHA-P IR Fourier spectrometer with OPUS software (Bruker, Germany). The samples of pure chemical salts manufactured by Sigma-Aldrich USA were used to validate the method. Salt mixtures were prepared in ratios of 10/90, 50/50 and 90/10. To assess the effect of the fraction size on the calculus component results, were used calculi of patients with urolithiasis. For each mixture were used 10 repeated measurements. Analysis of the composition of model salts showed that in the study of pure cystine salt CV(%) was 0,79%, calcium carbonate - 0,92%, sodium urate - 0,97%, calcium oxalate monohydrate - 4,94%, magnesium ammonium phosphate - 5,59%. And the most common components were analyzed in the composition of complex mixtures, including 90%, 50% and 10% of the investigated component. Calcium oxalate monohydrate has CV(%) 5.70% in mixture 9 part of it to one part of impurities, in mixture 50/50 - 21.57% and in 10/90 - 5.70%. For uric acid in 90/10 - 2.20%, in 50/50 - 10.09%, in 10/90 - 31.94%. For calcium carbonate in 90/10 - 9.02%, in 50/50 - 11.98%, in 10/90 - 24.70%. The dispersion analysis showed that the weighed portions of salts with a particle diameter of more than 0.8 mm provide reproducibility with a CV - 11.48%, with a diameter of 0.2-0.8 mm - 5.35%, and finally less than 0.1 mm - 2.28%. The accuracy of the method is high, but the reproducibility of the IR-spectroscopy method is relatively low in the analysis of stones of mixed composition, due to the greater error in the determination of impurities. Laboratories should pay special attention to optimizing sample preparation to ensure particle fineness less than 0.1 mm.

[The role of adipose tissue and laboratory predictors of primary osteoporosis.]

The purpose of this work was to determine the information content of alkaline phosphatase (ALP), total calcium (Ca) as predictors for the diagnosis of osteoporosis. By laboratory methods, 2451 people were divided into two groups according to the presence/absence of metabolic syndrome (MetS+ / MetS-): 1946 women (MetS- 1119, MetS+ 827) and 505 men (MetS- 264, MetS+ 241). Patients with laboratory signs of liver pathology are excluded. In women: MetS+ levels of ALP and Ca significantly differ from MetS- (p<0.0001), no differences were found for men. ALP synchronously change the indicators of TG, HDL, LDL, ALT, AST, Ca, demonstrating a positive relationship (p<0.001), the indicators do not exceed the threshold values. MetS- women in pre- and postmenopausal women significantly differ in ALP: 63.90 E / l vs 79.10 E / l (p<0.0001).

[Vitamin D and laboratory indicators of cardiovascular risk in the elderly.]

The aim of this work was to study the availability of vitamin D in the population of free living elderly people in St. Petersburg and its relationship with laboratory indicators of the risk of cardiovascular complications. In winter were surveyed 209 volunteers who did not take vitamin D during the previous 6 months, with 152 women and 57 men aged 71 to 91 years. In all the examined patients the concentration of D(OH) in serum was below 30 ng/ml (analyzer and reagents «Architect i1000SR, Abbott¼). No significant mutual effects were found between level 25(OH)D and lipid spectrum, hemoglobin A1C, testosterone, ultra-sensitive C-reactive protein. The close relationship between vitamin D(OH) concentration and brain natriuretic peptide (BNP) levels was characterized by rs=0.187 (p=0.007). In older people with severe vitamin deficiency (less than 10 ng/ml), the risk of elevated BNP levels was 2.6 times higher than in those with reduced vitamin levels (20-30 ng/ml).

[Methodological aspects of interpretation of thyroid-stimulating hormone reference intervals in the Northwest region megapolis hospital.]

The prevalence of subclinical hypothyroidism (SH) is large and according to various studies is from 3 to 21%. In the Russian Federation to date, there are no major epidemiological studies assessing the functional state of the thyroid gland. It seems relevant to study the TSH level in patients who turned to the clinical units of a large hospital in the North-West region to determine the prevalence of thyroid dysfunction in patients of different sex and age. 5,303 patients were examined, who applied to the I.P. Pavlov SPbSMU clinics for 2017. In all patients the level of TSH and free T4 was determined. SH was considered to increase the level of TSH more than 4.0 mIU/l at a normal level of free T4. Patients were divided into groups by age and TSH level in accordance with existing recommendations. Among the examined patients were 29.26% of men and 70.73% of women. The mean age was 55.08 ± 17.07 years. The TSH level had an abnormal distribution and averaged 2.77 mIU/l (TSH median 1.73 mIU/l). In women the level of TSH was significantly higher in all studied groups of patients (p = 0.0001). Among women, significant differences in the level of TSH between the elderly and young patients (p = 0.015) were found. The incidence of SH in the total group of patients was 10.1%. In the men surveyed, the incidence of SH was 7.3%, and in the female group - 11.3%. In the elderly patients, the incidence of subclinical hypothyroidism in women was 2 times higher than that of men. In most cases (77.4%) in patients with SH, the TSH level was in the range of 4.0-6.9 mIU / L. The clinical significance of minimal thyroid insufficiency requires further study.

[Diagnostic value of immunoglobulin free light chains at the debut of multiple sclerosis]. / Rol' opredeleniia svobodnykh legkikh tsepei immunoglobulinov v diagnostike debiuta rasseiannogo skleroza.

AIM: To evaluate the diagnostic value of determination of free immunoglobulin light chains (IgG) in the debut of multiple sclerosis (MS). MATERIAL AND METHODS: Data from 226 patients, including 111 patients with clinically isolated syndrome with conversion to multiple sclerosis within the first 2 years of the disease (group 1), 49 patients with clinically isolated syndrome who did not develop multiple sclerosis within the first 2 years of the disease (group 2), 20 patients with other inflammatory diseases of the central nervous system (group 3) were analyzed. The control group consisted of 46 patients with non-inflammatory diseases of the central nervous system. The clonality of immunoglobulins in the CSF, concentration of kappa and lambda free light chains and their ratio were studied. RESULTS: Concentrations of free light chains were significantly higher in the first group in comparison with group 2 and the control group, but didn't differ from group 3. In group 3, concentrations of free light chains were significantly higher compared to group 2 and controls. In oligoclonal-positive patients with clinically isolated syndrome (groups 1 and 2), concentrations of kappa and lambda free light chains were significantly higher than in oligoclonal-negative patients. The production of free light chains in patients from the first group was considerably higher than in group 2 regardless of the oligoclonal status. The concentration of kappa chains and quotient of kappa free light chains in the CSF had the best diagnostic characteristics. Their use, along with the evaluation of IgG clonality, reduced the risk of false-negative results by 50%. Regardless of other factors, elevated concentrations of kappa chains increase the likelihood of MS diagnosis by 9.718 times. CONCLUSION: The use of free light chains as a laboratory marker can increase the accuracy of MS diagnosis. These markers can help indirectly assess the risk of transformation of a clinically isolated syndrome into definite multiple sclerosis within the first 2 years of disease.

[The association of intrathecal production of immunoglobulin free light chains and progression of multiple sclerosis]. / Sviaz' intratekal'noi produktsii svobodnykh legkikh tsepei immunoglobulinov s progressirovaniem rasseiannogo skleroza.

AIM: To assess an impact of immunoglobulin free light chains (FLC) on short-term and long-term prognosis of clinical and radiological activity and progression of disability in multiple sclerosis (MS). MATERIAL AND METHODS: A sample of 381 patients with definite MS was divided into 2 groups. In group 1, lumbar puncture was performed at the time of clinically isolated syndrome, and patients were prospectively followed up to 2 years (short-term prognosis group, n=97). In group 2, MS was diagnosed immediately after lumbar puncture, and retrospective analysis of the disease course with the duration not less than 5 years was performed (long-term prognosis group, n=284). The Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Severity Score (MSSS) were used to assess patient's status. Concentrations of kappa and lambda FLC in the CSF (K-FLCCSF, L-FLCCSF) and serum (K-FLCSERUM, L-FLCSERUM) as well as quotients of concentrations (Q-K and Q-L) were determined. Patients were stratified into subgroups with high and low concentrations of K-FLC and L-FLC using cut-offs from our previous studies: K-FLCCSF=0.595 mcg/l and L-FLCCSF=0.127 mcg/l. RESULTS: In group 1, significant correlations were found only between EDSS score and concentrations of K-FLCCSF (r=0.377, p=0.00019) and Q-K (r=0.366, p=0.0012). FLC concentrations did not correlate with the number of relapses and new T2 lesions. The age and EDSS score at the disease onset didn't differ between patients with high and low K-FLC and L-FLC (K-FLCCSF: р=0.2658; L-FLCCSF: р=0.5502). A significant decrease of EDSS score after the disease onset was observed in all groups except for patients with high concentrations of K-FLCCSF (p=0.1844), so the EDSS score after 2 years was significantly higher in this subgroup of patients (p=0.0006). In group 2, significant correlations of K-FLC with EDSS score (r=0.181, p=0.002) and MSSS score (r=0.121, р=0.044) for long-term prognosis (median (IQR) = 8 (6-13) years) were found. No correlations of FLC concentrations with the number of relapses during the first 5 years were found. Survival analysis showed that high concentrations of K-FLCCSF were associated with the high risk of progression to EDSS 6 (HR=2.055, p=0.026) but not with EDSS 4 (HR=2.388, p=0.08). CONCLUSION: Concentrations of kappa FLC can help to define the prognosis of MS early at the disease course. Although low concentrations of FLC do not exclude a severe disease phenotype, patients with high K-FLCCSF concentrations are at greater risk for faster MS progression, probably, due to impaired reparation of neural tissue. Measurement of FLC concentrations can be used to determine a therapeutic tactics in patients with MS.

The Diagnostic Value of Alpha-1-Antitrypsin Phenotype in Patients with Granulomatosis with Polyangiitis.

The deficiency of alpha-1 protease inhibitor, or alpha-1-antitrypsin (A1AT), predisposes to chronic lung diseases and extrapulmonary pathology. Besides classical manifestations, such as pulmonary emphysema and liver disease, alpha-1-antitrypsin deficiency (A1ATD) is also known to be associated with granulomatosis with polyangiitis (GPA or Wegener's granulomatosis). The aim of our study was to evaluate the frequency of allelic isoforms of A1AT and their clinical significance among GPA patients. Detailed clinical information, including Birmingham Vasculitis Activity Score (BVAS), incidence of lung involvement, anti-proteinase 3 (PR3) antibodies concentrations, and other laboratory data were collected in 38 GPA patients. We also studied serum samples obtained from 46 healthy donors. In all collected samples A1AT phenotyping by isoelectrofocusing (IEF) and turbidimetric A1AT measurement were performed. Abnormal A1AT variants were found in 18.4% (7/38) of cases: 1 ZZ, 4 MZ, 2 MF, and only 1 MZ in control group (2%). The mean A1AT concentration in samples with atypical A1AT phenotypes was significantly lower (P = 0.0038) than in normal A1AT phenotype. We found that patients with abnormal A1AT phenotypes had significantly higher vasculitis activity (BVAS) as well as anti-PR3 antibodies concentration. We conclude that A1AT deficiency should be considered in all patients with GPA.

[The pathochemical characteristics of oligomeric forms of Tamm-Horsfall protein under urolithiasis].

The role of Tamm-Horsfall protein in pathogenesis of urolithiasis was analyzed. The study of oligomeric forms of protein was carried out using technique of dynamic light scattering. The sampling of 57 patients with urolithiasis and 51 patients of control group of comparative age and gender were examined. The degree of purification of Tamm-Horsfall protein was controlled using denaturant electrophoresis in polyacridine amyl gel. The reversing change of oligomeric form of protein with molecule size 2 Mda in polymeric form 28 Mda under impact of guanidinhydrochloride. Under urolithiasis, the form of protein associated with non-organic components and with size of macromolecular complex larger than 1500 nm was detected. The diagnostic criterion of urolithiasis was proposed based on totality of biochemical and biophysical analyses of urine.

[The detection of level of free light chains of immunoglobulins using enzyme-linked immunosorbent assay techniques for diagnostic of monoclonal gammopathy.]

The content of free light chains of immunoglobulins kappa and lambda and also ratio of their concentrations in blood serum are important diagnostic and prognostic markers in case of monoclonal gammopathy. The technique FreelightTM based on nephelometric detection of free light chains using polyclonal antibodies is one of common modes of detection of free light chains. The actual study was carried out with purpose of validating of national test-system for detection of level of free light chains in blood serum using technique of enzyme-linked immunosorbent assay. The samples of blood serum were taken from 89 healthy donors and 165 patients with monoclonal gammopathy. To detect the level of free light chains enzyme-linked immunosorbent assay testsystem "Polygnost" was used based on application of monoclonal a ntibodies. The number of analytical characteristics of reagents set was determined including limit of detection and range of linearity. The limit of detection of free light chains using enzymelinked immunosorbent assay test-system was two times lower than claimed by manufacturer of nephelometric set "FreelightTM". Hence, analytical characteristics of enzyme-linked immunosorbent assay set make it possible to detect the level of free light chains within range of standard values. The reference limits were established concerning concentration of free light chains kappa (3.25-15.81 mkg/ml), free light chains lambda (3.23-28.05 mkg/ml) and their ratio (0.3-1.9) in blood serum that factually matched the recommended intervals for "FreelightTM" set. In patients with monoclonal gammopathy the level of free light chains was reliably higher (p<0.01) as compared with control group of healthy donors. In case of paraproteinemia reliable alteration (p<0.01) of ratio free light chains kappa/free light chains lambda was observed in comparison with control group. The results of actual study testify that national enzyme-linked immunosorbent assay set has good analytical and diagnostic characteristics and it can be used in laboratory practice.

[THE TEST OF GENERATION OF THROMBIN IN DYNAMICS IN PATIENTS AFTER TRANSCUTANEOUS CORONARY INTERVENTION].

The article presents results of observation of generation of thrombin in patients with ischemic heart disease in different terms after transcutaneous coronary intervention. The sampling included 37 patients with stable ischemic heart disease. The control group included 30 healthy individuals. To study system of hemostasis of this category of patients the test of generation of thrombin and its modification with added thrombomodulin were applied for evaluating anti-coagulant activity of system of protein C. The comparison of indicators of test of generation of thrombin in patients with ischemic heart disease before operation and in individuals of control group revealed no reliable differences (p > 0.05). The observation of patients with stable ischemic heart disease in various time-frame after mechanical re-vascularization of myocardium established significant increasing of generation of thrombin and decreasing of anticoagulant activity of system of protein C at 1-3 day after operation (p < 0.05). The positive correlation was established between endogenous thrombin potential and annexin 5, an early marker of dysfunction of endothelium in mentioned time-frame after operation (p = 0.0008; r = 0.57). The significant increasing of content of anti-inflammatory markers of C-reactive protein and fibrinogen was observed at 1-3 day after transcutaneous coronary intervention (p < 0.05). In that way, the study data give evidence to hyper-coagulation in patients with stable ischemic heart disease in early time-frame after operation despite normal values of activated partial thromboplastin time, prothrombin time, D-dimer and applied standard disaggregant therapy.

[The clinical laboratory diagnostic as a part of clinical medicine.]

The rapid development of laboratory technologies and their translation directionality permit developing principles of personified medicine. The article considers new paradigm of manpower policy for developing necessary level of clinical laboratory consultation.

[THE CLINICAL LABORATORY MARKERS OF ATHEROSCLEROSIS IN PATIENTS WITH ATHEROTHROMBOTIC STROKE].

The laboratory biomarkers can effect on choice of tactics of treatment in patients with atherosclerotic stenosis ofcarotids and high risk of stroke. However, nowadays there is no established laboratory criteria of significant atherosclerotic affection of internal carotid. The purpose of study was to investigate informativeness of biomarkers of atherosclerosis in clinical molecuIar panel of expertise system of determining risk of stroke in patients with significant stenosis of carotid. The study included patients with 50-90% atherosclerotic stenosis of internal carotid in acute period of atherothrombotic stroke or transitory ischemic attack (group 1), patients with stable 50-90% atherosclerotic stenosis of inner carotid having no vascular events during 30 days before engaging into study (group II) and group of healthy volunteers without atherosclerosis of inner carotid. The examination of patients included anamnesis collection, evaluation of neurological status, analysis of serum level of biomarkers of atherosclerosis (lipoprotein-associatedphospholipase A2 (LP-PL A2), serum protein A associated with pregnancy (PA PP-A), lipoprotein (a) (LP(a)), asymmetric dimethylarginine (ADMA), C-reactive protein detected by highly sensitive technique (hsCRP) and lipid spectrum of blood) using enzyme-linked immunosorbent assay, duplex ultrasound scanning of brachiocephalic arteries. The stroke risk factors of other etiology were chosen as exclusion criteria except atherothrombotic one. The Mann-Whitney and Kruskal-Wallis tests were applied to establish group differences. The Data Mining techniques were applied to establish patterns of analyzing sample. Out of 356 examined patients, 30 patients of group 1, 51 patients of group II and 16 healthy volunteers were included in the study. All patients were comparable by gender and age (50-80 years). The serum level of hsCRP and ADMA in the group of patients of acutest period of ischemic stroke was significantly higher than in groups of patients with stable stenosis and healthy volunteers (p < 0.05). The comparison between three groups established no statistically significant differences in serum concentration of PAPP-A, LP-PL A2 and LP(a). The ADMA, hsCRP and PAPP-A can be recommended for including into clinical molecular panel for personalized diagnostic of causes of stroke along with clinical anamnestic data. The serum level of ADMA and hsCRP significantly increases in acute period of atherothrombotic stroke. The analysis of levels of ADMA, hsCR and PPAPP-A interpreted with regard to clinical anamnestic data can be proposed for enhancing quality of diagnostic of causes of stroke.

[THE COMPARISON OF TECHNIQUES OF ELECTROPHORESIS, IMMUNE TURBIDYNAMIC MEASUREMENT AND PHENOTYPING OF ALPHA-1-ANTITRYPSIN FOR DIAGNOSTIC OF ALPHA-1-ANTITRYPSIN INSUFFICIENCY].

The qualitative and quantitative deficiency of alpha-1-antitrypsin (A1AT) is an inherited factor of susceptibility to a number of conditions including chronic obstructive disease of lungs and primary emphysema and liver affection. The study was carried out to evaluate analysis of alpha-1-fraction (A1F) using zonal electrophoresis technique for detecting patients with alpha-1-antitrypsin insufficiency (A1ATI). The patients with decreased (group I) and normal (group II) A1F on proteinogram. The electrophoresis was applied using the system of capillary electrophoresis Capillaris-2 Flex Piercing (Sebia, France) and also system for electrophoresis in agarose gel SAS-1/SAS-2 (Helena Biosciences, Great Britain). The commercial kit Sentinel diagnostics (Italy) and biochemical analyzer A15 (Biosystems, Spain) were used for quantitative detecting of A1AT The study results demonstrated that decreasing of A1F on proteinogram correlated with lessening of concentration of A1ATI in blood serum and with presence of its pathological phenotype. The average values of concentration of A1AT in group I and group II made up to 1148 and 1738 mg/I correspondingly. The total rate of pathological phenotypes made up to 76% (19/25) in group I that reliably differed from indicators in group II--7.1% (2/28). Thereby, electrophoresis of proteins of blood serum can be sufficiently informative for primary selection of patients requiring examination for presence of A1ATI.

[Annexin-5 as a biochemical marker of early vascular disorders under chronic disease of kidneys].

The study evaluated the significance of annexin-5 as a biochemical marker of atherosclerosis in patients with chronic disease of kidneys. The sample consisted of 46 patients with chronic disease of kidneys without clinical symptoms of atherosclerosis. The indicators of lipidogram, intima-media complex of carotid artery reactivity of vessels of microcirculatory channel and concentration of annexin-5 are determined. The decrease of velocity of glomerular filtration is accompanied by the increase of concentration of annexin-5 related to indicators of lipidogram. The increase of concentration level of annexin-5 is accompanied by the most expressed dysfunction of endothelium. The increase 3a level of annexin-5 in blood of patients with chronic disease of kidneys is especially informative in case of lacking of clinical symptomatic of atherosclerosis and it testifies the presence of vasomotor endothelial dysfunction. The dynamic detection of concentration of annexin-5 can ameliorate the prognosis of possibility of development of cardio-vascular complications under diseases of kidneys.

[The directions and experiences of integration of clinical laboratory diagnostic and branch medicine].

The article considers the actual issues of teaching laboratory medicine to students of medical faculty and to physicians getting trained in different programs of postgraduate education. The major models of interaction between clinical physicians and specialists of laboratory diagnostic are considered. The proposed model of teaching of laboratory medicine is developed in collaboration with clinical chairs and is based on the principle of "clinical laboratory council of physicians". The analysis of clinical cases of specific patients and clinical analytical critiques are in the basement of the given system. The algorithm of considering one of situation tasks used in teaching is presented as example.

[The practice of development and implementation of quality management systems in medical laboratories. The GOST R ISO 15189-2009 "medical laboratories. The detailed requirements to quality and competence". Particular difficulties of global nature].

The article discusses the methodological issues related to the implementation of international principles of standardization in the format of GOST R ISO 9001-2008 "Quality management systems. Requirements", GOST R ISO 15189-2009 "Medical laboratories. The detailed requirements to quality and competence" and GOST R ISO 18113.1-5 "Medical items for diagnostics in vitro. Information provided by manufacturer (marking)". This approach legibly assigns the responsibility concerning the support of metrological correctness of laboratory measurements. The lacking of both full-value public and sectorial normative documentation and coordinated positions of Rosstandard and Minzdrav of Russia on functioning of medical laboratories is noted.

[Correlations between the levels of vitamin D, parathormone, calcium, blood phosphates in patients with chronic kidney disease not treated with kidney replacement therapy].

AIM: To characterize correlations between the levels of vitamin D, parathormone, calcium, blood phosphates in patients with different stages of chronic disease of the kidney (CDK) given no therapy replacing renal function (TRRF). MATERIAL AND METHODS: Serum levels of creatinine, electrolytes, parathormone (PTH), 25(OH)-vitamin D (calcidiol-CD), 1,25 (OH)2-vitamin D (calcitriol-CT), calcium (Ca) and phosphates (P) excretion with urine were studied in 465 patients aged 52.2 +/- 15.5 years with CDK stage I-V given no TRRF having mean glomerular filtration rate (GFR) 51.8 +/- 27.1 ml/min. RESULTS: A CT level lowered with CDK progression and directly correlated with GFR, blood levels of Ca and CD. Correlation with PTH was not found. CD did not correlate with GFR. PTH rose from stage II CDK and its concentration in the blood correlated negatively with GFR, blood Ca (in lesser degree), directly correlated with P. Ca lowered at stage V of CDK, P--at stage II, increased at stage IV. In reduction of GFR 24-h excretions of P and Ca diminished in spite of growth of their excreted fractions and were related directly with CT. CONCLUSION: A rise of PTH and fall of CT occur at early CDK stages. P disbolism seems to play a key role in genesis of hyperparathyrosis. We are the first to show lowering of 24-hour Ca and P excretion with CDK progression which may be caused by a progressive CT deficiency.