Valkude uuringute algoritm monoklonaalsete gammopaatiate korral

Eesti Arst 2023; 102(6–7):359–36

Luu ainevahetuse biokeemilised markerid Eesti fertiilses eas ja postmenopausi perioodis naistel

Luu ainevahetuse ealiste ja patoloogiliste muutuste täpsemaks hindamiseks kasutatakse biokeemilisi markereid, mis võimaldavad iseloomustada luu ainevahetuse erinevaid etappe. Hinnangute andmine eeldab täpsete referentsväärtuste olemasolu. Selles töös on erinevas eas Eesti naistel uuritud luukoe biokeemiliste markerite referentsväärtusi, kusjuures luustiku seisundit iseloomustati nimmelülide densitomeetria ja kannaluu kvantitatiivse ultraheliuuringu abil. Eesti Arst 2003; 82 (4): 270–27

an international multi center serum protein electrophoresis accuracy and m protein isotyping study part i factors impacting limit of quantitation of serum protein electrophoresis

AbstractBackgroundSerum protein electrophoresis (SPEP) is used to quantify the serum monoclonal component or M-protein, for diagnosis and monitoring of monoclonal gammopathies. Significant imprecision and inaccuracy pose challenges in reporting small M-proteins. Using therapeutic monoclonal antibody-spiked sera and a pooled beta-migrating M-protein, we aimed to assess SPEP limitations and variability across 16 laboratories in three continents.MethodsSera with normal, hypo- or hypergammaglobulinemia were spiked with daratumumab, Dara (cathodal migrating), or elotuzumab, Elo (central-gamma migrating), with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Provided with total protein (reverse biuret, Siemens), laboratories blindly analyzed samples according to their SPEP and immunofixation (IFE) or immunosubtraction (ISUB) standard operating procedures. Sixteen laboratories reported the perpendicular drop (PD) method of gating the M-protein, while 10 used tangent skimming (TS). A mean percent recovery range of 80%–120% was set as acceptable. The inter-laboratory %CV was calculated.ResultsGamma globulin background, migration pattern and concentration all affect the precision and accuracy of quantifying M-proteins by SPEP. As the background increases, imprecision increases and accuracy decreases leading to overestimation of M-protein quantitation especially evident in hypergamma samples, and more prominent with PD. Cathodal migrating M-proteins were associated with less imprecision and higher accuracy compared to central-gamma migrating M-proteins, which is attributed to the increased gamma background contribution in M-proteins migrating in the middle of the gamma fraction. There is greater imprecision and loss of accuracy at lower M-protein concentrations.ConclusionsThis study suggests that quantifying exceedingly low concentrations of M-proteins, although possible, may not yield adequate accuracy and precision between laboratories

Data underlying the research on Aortic lengths of the subjects estimated from CT images with jugulum to symphysis distance and demographic and anthropometric parameters

The objective of collected dataset was to develop multi-parameter linear models for the estimation of aortic length. The aortic length was determined using the CT images. The jugulum to symphysis distance was measured from body surface with a tape. The demographic and anthropometric parameters were determined either through measurement (e.g. weight of the subject) or using questionnaire

Prevalence of cardiovascular disease risk factors in Tallinn, Estonia

Background and objective: Cardiovascular diseases are still a major public health concern in Estonia despite the decline in the mortality rate during the past decade. For better preventive strategies we aimed to investigate the prevalence of cardiovascular disease risk factors and their relations with age, gender and ethnicity.Materials and methods: The cross-sectional study was carried out in Tallinn, Estonia. Two hundred individuals from each of the sex and 10-year age group (range 20–65 years of age) were randomly selected and invited to participate. Final study sample consisted of 511 men and 600 women (mean age of 46 years). Physiological measurements were taken and blood samples were drawn for standard measurements of the following markers: total cholesterol, high- and low-density lipoprotein cholesterol, apolipoproteins, triglycerides, glucose and inflammatory markers.Results: Overall, 31% of the study subjects had high blood pressure, 23% had metabolic syndrome, and 55% were overweight/obese. The prevalence of all risk factors increased with age amongst both genders. The proportion of individuals having increased cholesterol, apolipoprotein B-100, and homocysteine levels was very high amongst both genders (60–80%). More Russians and other ethnic minorities compared to ethnic Estonians had calculated 10-year CHD risk ≥ 10%.Conclusions: The study established a high prevalence of cardiovascular disease risk factors in Estonian adults (20–65 years of age). Younger portion of the population and some extent ethnic considerations should be taken into account when designing future studies, health prevention activities and interventions

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part I: factors impacting limit of quantitation of serum protein electrophoresis

Background Serum protein electrophoresis (SPEP) is used to quantify the serum monoclonal component or M-protein, for diagnosis and monitoring of monoclonal gammopathies. Significant imprecision and inaccuracy pose challenges in reporting small M-proteins. Using therapeutic monoclonal antibody-spiked sera and a pooled beta-migrating M-protein, we aimed to assess SPEP limitations and variability across 16 laboratories in three continents. Methods Sera with normal, hypo- or hypergammaglobulinemia were spiked with daratumumab, Dara (cathodal migrating), or elotuzumab, Elo (central-gamma migrating), with concentrations from 0.125 to 10 g/L (n\u2009=\u200962) along with a beta-migrating sample (n\u2009=\u20099). Provided with total protein (reverse biuret, Siemens), laboratories blindly analyzed samples according to their SPEP and immunofixation (IFE) or immunosubtraction (ISUB) standard operating procedures. Sixteen laboratories reported the perpendicular drop (PD) method of gating the M-protein, while 10 used tangent skimming (TS). A mean percent recovery range of 80%-120% was set as acceptable. The inter-laboratory %CV was calculated. Results Gamma globulin background, migration pattern and concentration all affect the precision and accuracy of quantifying M-proteins by SPEP. As the background increases, imprecision increases and accuracy decreases leading to overestimation of M-protein quantitation especially evident in hypergamma samples, and more prominent with PD. Cathodal migrating M-proteins were associated with less imprecision and higher accuracy compared to central-gamma migrating M-proteins, which is attributed to the increased gamma background contribution in M-proteins migrating in the middle of the gamma fraction. There is greater imprecision and loss of accuracy at lower M-protein concentrations. Conclusions This study suggests that quantifying exceedingly low concentrations of M-proteins, although possible, may not yield adequate accuracy and precision between laboratories

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part II: limit of detection and follow-up of patients with small M-proteins

Background Electrophoretic methods to detect, characterize and quantify M-proteins play an important role in the management of patients with monoclonal gammopathies (MGs). Significant uncertainty in the quantification and limit of detection (LOD) is documented when M-proteins are <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. Methods Sera with normal, hypo- or hyper-gammaglobulinemia were spiked with daratumumab or elotuzumab, with concentrations from 0.125 to 10 g/L (n\u2009=\u200962) along with a beta-migrating sample (n\u2009=\u20099). Laboratories blindly analyzed samples according to their serum protein electrophoresis (SPEP)/isotyping standard operating procedures. LOD and intra-laboratory percent coefficient of variation (%CV) were calculated and further specified with regard to the method (gel/capillary electrophoresis [CZE]), gating strategy (perpendicular drop [PD]/tangent skimming [TS]), isotyping (immunofixation/immunosubtraction [ISUB]) and manufacturer (Helena/Sebia). Results All M-proteins 651 g/L were detected by SPEP. With isotyping the LOD was moderately more sensitive than with SPEP. The intensity of polyclonal background had the biggest negative impact on LOD. Independent of the method used, the intra-laboratory imprecision of M-protein quantification was small (mean CV\u2009=\u20095.0%). Low M-protein concentration and high polyclonal background had the strongest negative impact on intra-laboratory precision. All laboratories were able to follow trend of M-protein concentrations down to 1 g/L. Conclusions In this study, we describe a large variation in the reported LOD for both SPEP and isotyping; overall LOD is most affected by the polyclonal immunoglobulin background. Satisfactory intra-laboratory precision was demonstrated. This indicates that the quantification of small M-proteins to monitor patients over time is appropriate, when subsequent testing is performed within the same laboratory