An improved indirect approach for determining reference limits from intra-laboratory data bases exemplified by concentrations of electrolytes / Ein verbesserter indirekter Ansatz zur Bestimmung von Referenzgrenzen mittels intra-laboratorieller Datensätze am Beispiel von Elektrolyt-Konzentrationen

2009 ◽  
Vol 33 (2) ◽  
pp. 52-66 ◽  
Author(s):  
Farhad Arzideh ◽  
Gunnar Brandhorst ◽  
Eberhard Gurr ◽  
Wilhelm Hinsch ◽  
Torsten Hoff ◽  
...  
Keyword(s):  
Laboratory Data ◽  
Data Bases ◽  
Indirect Approach ◽  
Reference Limits

scholarly journals Determination of high sensitive cardiac troponin I 99th percentile upper reference limits in a healthy Pakistani population

2020 ◽  
Vol 36 (6) ◽  
Author(s):  
Kulsoom Bahadur ◽  
Aamir Ijaz ◽  
Momin Salahuddin ◽  
Aftab Alam
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Laboratory Data ◽  
Cardiac Troponin I ◽  
Medical Institute ◽  
Pakistani Population ◽  
Reference Limits ◽  
Males And Females ◽  
Gender Specific

Objective: This study aims to establish the 99th percentile upper reference limits of high sensitive cardiac troponin I in a healthy Pakistani population. Methods: It was an Observational cohort study carried out in Department of Chemical Pathology and Endocrinology Rehman Medical Institute Peshawar, over the period of one year (January 2019- December 2019). Total 299 cardio-healthy males and females were interviewed and taken past medical history. Based on history, clinical examination, echocardiogram and laboratory data including results of estimated glomerular filtration rate (eGFR) and N-terminal pro-B-type natriureteric peptide (NT-proBNP), subjects with possible subclinical diseases were excluded. High Sensitive Cardiac Troponin I (hs-cTtrop I) was analysed on Abbot ARCHITECT STAT ci8200 using chemiluminescent immunoassay technique. The 99th percentile upper reference limit (URL) of hs-cTtrop I was determined using a non-parametric statistic, while gender specific results were compared. Results: In this study, 178 males (59.5%) and 121 females (40.5%) were included. The median Interquartile ranges (IQR) of age was 57 (11.6) for males and 56 (13) for females. The 99th percentile URL hs-cTtrop I was found to be 33.9 ng/L, while gender specific values were 38.41ng/L and 15.73ng/L for males and females, respectively (p= 0.0045). Conclusion: High sensitivity cardiac troponin I 99th percentile URL in our study population was found to be 33.9 ng/L with gender specific values being 38.41 ng/L and 15.73ng/L for males and females respectively. Troponin I in males was substantially high in comparison with females. doi: https://doi.org/10.12669/pjms.36.6.2328 How to cite this:Bahadur K, Ijaz A, Salahuddin M, Alam A. Determination of high sensitive cardiac troponin I 99th percentile upper reference limits in a healthy Pakistani population. Pak J Med Sci. 2020;36(6):---------. doi: https://doi.org/10.12669/pjms.36.6.2328 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

scholarly journals The influence of sampling time on indirect reference limits, decision limits, and the estimation of biological variation of random plasma glucose concentrations

2021 ◽  
Vol 45 (2) ◽  
pp. 111-119 ◽  
Author(s):  
Mustafa Özcürümez ◽  
Farhad Arzideh ◽  
Antje Torge ◽  
Anja Figge ◽  
Rainer Haeckel ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Large Scale ◽  
Laboratory Data ◽  
Sample Collection ◽  
University Hospitals ◽  
Reference Limit ◽  
Average Decrease ◽  
Glucose Levels ◽  
Reference Limits ◽  
Upper Reference Limit

Abstract Objectives Plasma glucose concentrations exhibit a pronounced daytime-dependent variation. The oscillations responsible for this are currently not considered in the determination of reference limits (RL) and decision limits. Methods We characterized the daily variation inherent in large-scale laboratory data from two different university hospitals (site 1 n=513,682, site 2 n=204,001). Continuous and distinct RL for daytime and night were estimated. Diurnal characteristics of glucose concentrations were further investigated by quantile regression analyses introducing age and cosinor-functions as predictors in the model. Results Diurnal variations expressed as amplitude/Midline Estimating Statistic of Rhythm (MESOR) ratio, averaged 7.7% (range 5.9–9.3%). The amplitude of glucose levels decreased with increasing concentrations. Between 06:00 and 10:00 h an average decrease of 4% has to be considered. Nocturnal glucose samples accounted for only 5% of the total amount but contributed to 19.5% of all findings over 11.1 mmol/L. Partitioning of RL between day and night is merely justified for the upper reference limit. The nocturnal upper RLs for both genders differed from those obtained during the day by 11.0 and 10.6% at site 1 and by 7.6 and 7.5% at site 2. Conclusions We conclude that indirect approaches to estimate upper RL of random plasma glucose concentrations require stratification concerning the time of sample collection.

Iterpretation of clinical chemical data with the aid of automatic data processing.

1976 ◽  
Vol 22 (10) ◽  
pp. 1555-1561 ◽  
Author(s):  
D S Young
Keyword(s):  
Laboratory Data ◽  
Data Bases ◽  
Automatic Data ◽  
Use Of Data ◽  
Clinical Laboratories ◽  
Factors Influencing ◽  
Clinical Chemical ◽  
Diagnostic Applications ◽  
References Values

Abstract I summarize conventional applications of computers in clinical laboratories and discuss the possible role of the computer in providing assistance in interpretation of laboratory data through the use of data bases. The data bases include effects of drugs on the results of laboratory tests, factors influencing references values, and conversion factors for converting data from conventional units to SIunits. Reported diagnostic applications of the computer are discussed with reference to both clinically oriented and laboratory oriented programs.

scholarly journals Indirect Reference Intervals: Harnessing the Power of Stored Laboratory Data.

2019 ◽  
Vol 40 (2) ◽  
pp. 99-111 ◽  
Keyword(s):  
Data Analysis ◽  
Traditional Approach ◽  
Laboratory Data ◽  
Age Groups ◽  
Reference Interval ◽  
Reference Intervals ◽  
Indirect Approach ◽  
Distribution Of Values ◽  
Alternative Approach ◽  
Indirect Technique

Reference intervals are relied upon by clinicians when interpreting their patients’ test results. Therefore, laboratorians directly contribute to patient care when they report accurate reference intervals. The traditional approach to establishing reference intervals is to perform a study on healthy volunteers. However, the practical aspects of the staff time and cost required to perform these studies make this approach difficult for clinical laboratories to routinely use. Indirect methods for deriving reference intervals, which utilise patient results stored in the laboratory’s database, provide an alternative approach that is quick and inexpensive to perform. Additionally, because large amounts of patient data can be used, the approach can provide more detailed reference interval information when multiple partitions are required, such as with different age-groups. However, if the indirect approach is to be used to derive accurate reference intervals, several considerations need to be addressed. The laboratorian must assess whether the assay and patient population were stable over the study period, whether data ‘clean-up’ steps should be used prior to data analysis and, often, how the distribution of values from healthy individuals should be modelled. The assumptions and potential pitfalls of the particular indirect technique chosen for data analysis also need to be considered. A comprehensive understanding of all aspects of the indirect approach to establishing reference intervals allows the laboratorian to harness the power of the data stored in their laboratory database and ensure the reference intervals they report are accurate.

Analytical goals for coagulation tests based on biological variation

2004 ◽  
Vol 42 (1) ◽  
Author(s):  
Yui Wada ◽  
Masako Kurihara ◽  
Mitsuko Toyofuku ◽  
Minako Kawamura ◽  
Hiroko Iida ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Clinical Laboratory ◽  
Laboratory Data ◽  
Biological Variation ◽  
University Hospital ◽  
Healthy Individuals ◽  
Coagulation Tests ◽  
Reference Limits ◽  
Clinical Chemical ◽  
Control Plasma

AbstractAllowable imprecision and bias reference limits for laboratory data can be calculated based on measurements of biological variation. Although biological variation of clinical chemical data has been reported from many laboratories, there have been few reports of biological variation in coagulation tests. In this study, we calculated the biological variation of 13 coagulation tests in the clinical laboratory of Kyushu University Hospital and determined allowable imprecision and bias limits of variation. The participating subjects were 17 healthy individuals: three males and two females in their 20s, two males and two females in their 30s, one male and four females in their 40s, and two males and one female in their 50s. Monthly measurements were performed before breakfast 12 times from June 2001 to May 2002 and allowable imprecision and bias limits were calculated. Taken together with coefficient of variation of control plasma used in daily laboratory work at the hospital, the allowable imprecision limits of intra-laboratory variation determined in this study appear to be in attainable ranges.

scholarly journals Indirect Reference Intervals: Harnessing the Power of Stored Laboratory Data

10.33176/test ◽  
2019 ◽  
Vol 40 (2) ◽  
pp. 99-111
Keyword(s):  
Data Analysis ◽  
Traditional Approach ◽  
Laboratory Data ◽  
Age Groups ◽  
Reference Interval ◽  
Reference Intervals ◽  
Indirect Approach ◽  
Distribution Of Values ◽  
Alternative Approach ◽  
Indirect Technique

Reference intervals are relied upon by clinicians when interpreting their patients’ test results. Therefore, laboratorians directly contribute to patient care when they report accurate reference intervals. The traditional approach to establishing reference intervals is to perform a study on healthy volunteers. However, the practical aspects of the staff time and cost required to perform these studies make this approach difficult for clinical laboratories to routinely use. Indirect methods for deriving reference intervals, which utilise patient results stored in the laboratory’s database, provide an alternative approach that is quick and inexpensive to perform. Additionally, because large amounts of patient data can be used, the approach can provide more detailed reference interval information when multiple partitions are required, such as with different age-groups. However, if the indirect approach is to be used to derive accurate reference intervals, several considerations need to be addressed. The laboratorian must assess whether the assay and patient population were stable over the study period, whether data ‘clean-up’ steps should be used prior to data analysis and, often, how the distribution of values from healthy individuals should be modelled. The assumptions and potential pitfalls of the particular indirect technique chosen for data analysis also need to be considered. A comprehensive understanding of all aspects of the indirect approach to establishing reference intervals allows the laboratorian to harness the power of the data stored in their laboratory database and ensure the reference intervals they report are accurate.

scholarly journals Calculation of indirect reference intervals of plasma lipase activity of adults from existing laboratory data based on the Reference Limit Estimator integrated in the OPUS::L information system

2021 ◽  
Vol 45 (2) ◽  
pp. 131-134
Author(s):  
Britta Amodeo ◽  
Aline Schindler ◽  
Ulrike Schacht ◽  
Hans Günther Wahl
Keyword(s):  
Information System ◽  
Lipase Activity ◽  
Clinical Chemistry ◽  
Laboratory Data ◽  
Direct Methods ◽  
Reference Interval ◽  
Reference Intervals ◽  
Specific Reference ◽  
Reference Limit ◽  
Reference Limits

Abstract Objectives Most laboratories have difficulties to determine their own reference intervals for the diagnostic evaluation of patient results by direct methods. Therefore, data is often just taken from the literature or package inserts of the analytical tests. Methods The section on Reference Limits of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) first uploaded the Reference Limit Estimator (RLE) as an R-program with MS Excel-interface on the DGKL home page and now this tool is implemented in the commercial Laboratory Information System OPUS::L (OSM AG Essen, Germany). We used this OPUS::L “Population specific Reference Limits” tool online with our laboratory database. First calculations were done using the example of lipase. Results The manufacturer’s original reference interval for lipase 12–53 U/L (adults) was changed to age dependent upper reference limits of <41 U/L (<20 years), <60 U/L (20–80 years) and <70 U/L (>80 years). Conclusions By means of the OPUS::L “Population specific Reference Limits” tool we were able to establish our laborarotry specific reference interval for plasma lipase activity. The new reference limits helped to solve an old problem of implausible low elevated lipase values.

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