scholarly journals Recommended changes of the current version of the German Rili-BAEK

2019 ◽  
Vol 43 (5) ◽  
pp. 225-233 ◽  
Author(s):  
Christian Beier
Keyword(s):  
Quality Assurance ◽  
Statistical Significance ◽  
Reference Intervals ◽  
Control Measures ◽  
Medical Laboratory ◽  
Patient Specific ◽  
Internal Quality ◽  
Specific Reference ◽  
Special Focus ◽  
Age Related

Abstract A number of improvement proposals and corrections of the German Rili-BAEK (Guideline of the German Medical Association on Quality Assurance in Medical Laboratory Examinations) are discussed with special focus on the internal and external quality assurance (IQA/EQA) as well as reference intervals for quantitative results. Particular attention is paid to reconsider the retrospective analysis of control measurements. Such an analysis can be very useful to monitor establishing errors of measurement even before they become critical. The present method “Quadratischer Mittelwert der Messabweichung (QMMA)” has proved to be ineffective. Furthermore, the current idea of a common limit for single control measures and the retrospective statistics must be revised. As a more sophisticated concept, the novel Adaptive Retrospective Monitoring (ARM) has been developed. ARM is recommended as the new minimum requirement for the entire internal quality assurance. Further proposals to enhance clarity are given concerning the release decisions of medical devices and the EQA. Individualized medicine begins with a patient-specific interpretation of analytic results. This requires standardized subgroup-specific reference intervals with smooth age-related adaptations. Only large laboratories are able to ensure the desired specificity and a sufficient statistical significance of self-developed in-laboratory reference intervals. Hence, the need of a central database for harmonized reference intervals is discussed and recommended. Suitable and consistent reference intervals are also an essential prerequisite for unitless laboratory values like the zlog value.

scholarly journals Impact of age, body weight and metabolic risk factors on steroid reference intervals in men

2020 ◽  
Vol 182 (5) ◽  
pp. 459-471
Author(s):  
Marco Mezzullo ◽  
Guido Di Dalmazi ◽  
Alessia Fazzini ◽  
Margherita Baccini ◽  
Andrea Repaci ◽  
...  
Keyword(s):  
Risk Factors ◽  
Reference Intervals ◽  
Metabolic Risk Factors ◽  
Specific Reference ◽  
Metabolic Risk ◽  
Cross Sectional ◽  
Cholesterol Ratio ◽  
Age Related ◽  
Reference Limits ◽  
17 Hydroxyprogesterone

Objective To evaluate the independent impact of age, obesity and metabolic risk factors on 13 circulating steroid levels; to generate reference intervals for adult men. Design Cross-sectional study. Methods Three hundred and fifteen adults, drug-free and apparently healthy men underwent clinical and biochemical evaluation. Thirteen steroids were measured by LC-MS/MS and compared among men with increasing BMI. Moreover, the independent impact of age, BMI and metabolic parameters on steroid levels was estimated. Upper and lower reference limits were generated in steroid-specific reference sub-cohorts and compared with dysmetabolic sub-cohorts. Results We observed lower steroid precursors and testosterone and increase in estrone levels in men with higher BMI ranges. By multivariate analysis, 17-hydroxyprogesterone and dihydrotestosterone decreased with BMI, while cortisol decreased with waist circumference. Estrone increased with BMI and systolic blood pressure. Testosterone decreased with worsening insulin resistance. 17-hydroxypregnenolone and corticosterone decreased with increasing total/HDL-cholesterol ratio. Age-related reference intervals were estimated for 17-hydroxypregnenolone, DHEA, 17-hydroxyprogesterone, corticosterone, 11-deoxycortisol, cortisol and androstenedione, while age-independent reference intervals were estimated for progesterone, 11-deoxycorticosterone, testosterone, dihydrotestosterone, estrone and estradiol. Testosterone lower limit was 2.29 nmol/L lower (P = 0.007) in insulin resistant vs insulin sensitive men. Furthermore, the upper limits for dihydrotestosterone (−0.34 nmol/L, P = 0.045), cortisol (−87 nmol/L, P = 0.045–0.002) and corticosterone (−10.1 nmol/L, P = 0.048–0.016) were lower in overweight/obese, in abdominal obese and in dyslipidaemic subjects compared to reference sub-cohorts, respectively. Conclusions Obesity and mild unmedicated metabolic risk factors alter the circulating steroid profile and bias the estimation of reference limits for testosterone, dihydrotestosterone, cortisol and corticosterone. Applying age-dependent reference intervals is mandatory for steroid precursors and corticosteroids.

scholarly journals Establishing laboratory-specific reference intervals for TSH and fT4 by use of the indirect Hoffman method

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0261715
Author(s):  
Sylwia Płaczkowska ◽  
Małgorzata Terpińska ◽  
Agnieszka Piwowar
Keyword(s):  
Low Cost ◽  
Adult Population ◽  
Age Groups ◽  
Large Data ◽  
Reference Intervals ◽  
Medical Laboratory ◽  
Specific Reference ◽  
Medical Decisions ◽  
Indirect Methods ◽  
Laboratory Information Systems

Background The results of examinations of laboratory parameters are the basis of appropriate medical decisions. The availability of reliable and accurate reference intervals (RIs) for each laboratory parameter is an integral part of its appropriate interpretation. Each medical laboratory should confirm their RIs. Up-to-date reference intervals for thyroid function hormones are still a matter of ongoing controversy. The aim of the study was the application of the indirect Hoffman method to determine RIs for TSH and fT4 based on the large data pools stored in laboratory information systems and the comparison of these RIs to generally used RIs. Material and methods The TSH and fT4 routine examination results of hospitalized and outpatient populations were collected over five years (2015–2019), and reference limits were established by the improved Hoffmann method after the exclusion of outliers. Comparative verification of established RIs was conducted with the RIs values provided by test manufacturers and literature data. Results Various RIs were observed in different age groups in the examined populations. For TSH, RIs varied between different age groups, with a narrower range of RIs in the studied adult population and a shift of both reference boundaries toward higher values in comparison to manufacturers’ data among children. RIs estimated for fT4 were very similar to the manufacturer and literature data. Conclusion Thyroid hormone levels change during a person’s lifetime and vary between sexes, but this difference does not always influence the clinical interpretation of laboratory results in the context of RIs. The use of indirect methods is justified due to the ease and low cost of their application.

scholarly journals Nomogram of age-specific anti-Müllerian hormone levels in healthy Egyptian females

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254858
Author(s):  
Eman Ahmed El-Attar ◽  
Tamer A. Hosny ◽  
Kiyoshi Ichihara ◽  
Rania N. Bedair ◽  
Ahmed Salah El-Din Tork
Keyword(s):  
Reference Interval ◽  
Reference Intervals ◽  
Specific Reference ◽  
Clinical Settings ◽  
Power Transformation ◽  
Serum Samples ◽  
Female Age ◽  
Age Related ◽  
Age Dependent ◽  
Age Range

Background Anti-Müllerian hormone (AMH) is an important determinant of ovarian reserve in fertility workups in many clinical settings. Thus, we investigated the age dependent decline in AMH specific to the Egyptian population and sought to establish an age dependent reference interval parametrically. Methods Serum samples were collected from 841 apparently healthy women. AMH was measured using an electro-chemiluminescent technique. Box-Cox power transformation was used to make the AMH distribution Gaussian for parametric derivation of reference intervals. Results Power of 0.4 was found optimal for Gaussian transformation of AMH reference values. We demonstrate the strong negative relation between circulating AMH and female age with Spearman’s correlation coefficient of rS = −0.528. Age-specific reference interval was determined for every 5 years of age from 16 to 49, and nomogram was constructed by smoothing the lines connecting adjacent lower and upper reference limits. Conclusion The age-specific reference intervals and the age-AMH nomogram could be valuable in the clinical practice of in reproductive medicine. To our knowledge, this is the first study to confirm AMH levels in Egyptian females. We were able to explore age-related AMH levels specific to Egyptian females in the fertile age group and to treat skewed AMH data in a multi-step scheme using power transformation. Thus, a more accurate nomogram was constructed accommodating a profile delineated for a wide age range and a rescaled AMH axis improving its usability.

Trimester-Specific Reference Intervals of Serum Urea, Creatinine, and Uric Acid Among Healthy Pregnant Women in Zhengzhou, China

2020 ◽  
Author(s):  
Yuhua Gao ◽  
Jia Jia ◽  
Xianan Liu ◽  
Shuren Guo ◽  
Liang Ming
Keyword(s):  
Uric Acid ◽  
Kidney Disease ◽  
Pregnant Women ◽  
Age Groups ◽  
Serum Levels ◽  
Reference Intervals ◽  
Specific Reference ◽  
Serum Urea ◽  
Age Related ◽  
In Pregnancy

Abstract Objective To verify the differences in serum levels of urea, creatinine, and uric acid (UA) between pregnant and nonpregnant women and establish specific reference intervals of serum urea, creatinine, and UA for pregnant women, and thus help for the detection of kidney disease in pregnancy. Methods Based on the selection criteria, 1312 apparently healthy pregnant women and 1301 nonpregnant women were enrolled in this study. The levels of serum urea, creatinine, and UA were compared between the pregnant and nonpregnant women. The differences in the 3 indicators among different age groups and trimesters in pregnant women were studied. Finally, reference intervals were established by nonparametric methods according to the recommendation of Clinical and Laboratory Standards Institute guideline C28-A3. Results Compared with nonpregnant women, pregnant women had a significantly lower level of serum urea, creatinine, and UA (all P <.01), and no significant age-related differences in the 3 indicators were observed among the pregnant women (P >.05). However, the levels of these indicators were significantly different among the 3 trimesters (all P <.01 or P =.01). Accordingly, trimester-specific reference intervals of serum urea (1.6–4.4 mmol/L; 1.6–4.2 mmol/L; 1.6–4.4 mmol/L), creatinine (36–68 μmol/L; 34–66 μmol/L; 36–68 μmol/L), and UA (122–297 μmol/L; 129–327 μmol/L; 147–376 μmol/L) for trimesters 1, 2, and 3, respectively, were established. Conclusion These newly established reference intervals will be valuable for the detection and monitoring of kidney disease in pregnancy.

scholarly journals Establishing Laboratory-Specific Reference Intervals for TSH and fT4 by use of the Indirect Hoffman Method

2021 ◽  
Author(s):  
Sylwia Płaczkowska ◽  
Małgorzata Terpińska ◽  
Agnieszka Piwowar
Keyword(s):  
Low Cost ◽  
Adult Population ◽  
Age Groups ◽  
Large Data ◽  
Reference Intervals ◽  
Medical Laboratory ◽  
Specific Reference ◽  
Medical Decisions ◽  
Indirect Methods ◽  
Laboratory Information Systems

Abstract Background: The results of examinations of laboratory parameters are the basis of appropriate medical decisions. The availability of reliable and accurate reference intervals (RIs) for each laboratory parameter is an integral part of its appropriate interpretation. Each medical laboratory should confirm their RIs. Up to date reference intervals for thyroid function hormones are still a matter of ongoing controversy. The aim of the study was application of the indirect Hoffman method to determine RIs for TSH and fT4 based on the large data pools stored in laboratory information systems, and the comparison of these RIs to generally used RIs.Material and methods: The TSH and fT4 routine examination results of a hospitalized and outpatients population over five years (2015-2019) were collected, and reference limits were established by the improved Hoffmann method after the exclusion of outliers. Comparative verification of established RIs was conducted with the RIs values provided by test manufacturers and literature data.Results: The various RIs in different age groups in examined populations were observed. For TSH RIs varied between different age groups, with a narrower range of RIs in the studied adult population, while for children, a shift of both reference boundaries toward higher values in comparison to manufacturers' data was observed. RIs estimated for fT4 were very similar to the manufacturer and literature data.Conclusion: Thyroid hormone levels change during a person's lifetime and vary between sexes, but this difference does not always influence the clinical interpretation of laboratory results in the context of RIs. The use of indirect methods is justified due to the ease and low cost of their application.

scholarly journals Genetic biomarkers in the VEGF pathway predicting response to anti-VEGF therapy in age-related macular degeneration

2019 ◽  
Vol 4 (1) ◽  
pp. e000273
Author(s):  
Irina Balikova ◽  
Laurence Postelmans ◽  
Brigitte Pasteels ◽  
Pascale Coquelet ◽  
Janet Catherine ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Macular Degeneration ◽  
Treatment Response ◽  
Multiple Testing ◽  
Age Related Macular Degeneration ◽  
Patient Specific ◽  
Multiple Testing Correction ◽  
Anti Vegf ◽  
Age Related ◽  
Vegf Pathway

ObjectiveAge-related macular degeneration (ARMD) is a leading cause of visual impairment. Intravitreal injections of anti-vascular endothelial growth factor (VEGF) are the standard treatment for wet ARMD. There is however, variability in patient responses, suggesting patient-specific factors influencing drug efficacy. We tested whether single nucleotide polymorphisms (SNPs) in genes encoding VEGF pathway members contribute to therapy response.Methods and analysisA retrospective cohort of 281 European wet ARMD patients treated with anti-VEGF was genotyped for 138 tagging SNPs in the VEGF pathway. Per patient, we collected best corrected visual acuity at baseline, after three loading injections and at 12 months. We also registered the injection number and changes in retinal morphology after three loading injections (central foveal thickness (CFT), intraretinal cysts and serous neuroepithelium detachment). Changes in CFT after 3 months were our primary outcome measure. Association of SNPs to response was assessed by binomial logistic regression. Replication was attempted by associating visual acuity changes to genotypes in an independent Japanese cohort.ResultsAssociation with treatment response was detected for seven SNPs, including in FLT4 (rs55667289: OR=0.746, 95% CI 0.63 to 0.88, p=0.0005) and KDR (rs7691507: OR=1.056, 95% CI 1.02 to 1.10, p=0.005; and rs2305945: OR=0.963, 95% CI 0.93 to 1.00, p=0.0472). Only association with rs55667289 in FLT4 survived multiple testing correction. This SNP was unavailable for testing in the replication cohort. Of six SNPs tested for replication, one was significant although not after multiple testing correction.ConclusionIdentifying genetic variants that define treatment response can help to develop individualised therapeutic approaches for wet ARMD patients and may point towards new targets in non-responders.

scholarly journals Towards CRISP-ML(Q): A Machine Learning Process Model with Quality Assurance Methodology

2021 ◽  
Vol 3 (2) ◽  
pp. 392-413
Author(s):  
Stefan Studer ◽  
Thanh Binh Bui ◽  
Christian Drescher ◽  
Alexander Hanuschkin ◽  
Ludwig Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Quality Assurance ◽  
Process Model ◽  
Practical Experience ◽  
Special Focus ◽  
Close Monitoring ◽  
Machine Learning Applications ◽  
Project Organizations ◽  
Considerable Impact ◽  
Learning Development

Machine learning is an established and frequently used technique in industry and academia, but a standard process model to improve success and efficiency of machine learning applications is still missing. Project organizations and machine learning practitioners face manifold challenges and risks when developing machine learning applications and have a need for guidance to meet business expectations. This paper therefore proposes a process model for the development of machine learning applications, covering six phases from defining the scope to maintaining the deployed machine learning application. Business and data understanding are executed simultaneously in the first phase, as both have considerable impact on the feasibility of the project. The next phases are comprised of data preparation, modeling, evaluation, and deployment. Special focus is applied to the last phase, as a model running in changing real-time environments requires close monitoring and maintenance to reduce the risk of performance degradation over time. With each task of the process, this work proposes quality assurance methodology that is suitable to address challenges in machine learning development that are identified in the form of risks. The methodology is drawn from practical experience and scientific literature, and has proven to be general and stable. The process model expands on CRISP-DM, a data mining process model that enjoys strong industry support, but fails to address machine learning specific tasks. The presented work proposes an industry- and application-neutral process model tailored for machine learning applications with a focus on technical tasks for quality assurance.

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