Short- and long-term biological variation in analytes in urine of apparently healthy individuals.

1981 ◽  
Vol 27 (4) ◽  
pp. 569-573 ◽  
Author(s):  
M D Shephard ◽  
L A Penberthy ◽  
C G Fraser
Keyword(s):  
Total Protein ◽  
Analytical Methods ◽  
Biological Variation ◽  
Healthy Individuals ◽  
Significant Percentage ◽  
Short And Long Term ◽  
Sodium Urate ◽  
Urine Specimens ◽  
Apparently Healthy

Abstract Intra-individual, interindividual, and analytical components of variation for each of 10 urine analytes were estimated from results obtained on analysis of urine specimens from 10 apparently healthy young men. In spot urines, urea and osmolality showed strong individuality, but intra-individual variances were larger than interindividual variances for sodium, urate, phosphate, and glucose. Urea and osmolality displayed strong individuality in daily urines, whereas sodium (when results were expressed in output terms), urate, potassium, and total protein (when results were expressed in concentration units) had intra-individual variances larger than interindividual variances. In monthly urines, calcium and glucose, in concentration terms, and phosphate, in output terms, exhibited strongest individuality. Analytical variance was a significant percentage of the total variance for total protein and glucose; the analytical methods we used for these analytes were probably unsatisfactory. A series of analytical goals for imprecision, based on biological variation, were derived. Although these goals may not be applicable in all clinical situations, they represent the beginning of a data base in the literature.

Short- and long-term biological variation of cardiac troponin I in healthy individuals, and patients with end-stage renal failure requiring haemodialysis or cardiomyopathy

2020 ◽  
Vol 58 (11) ◽  
pp. 1941-1949
Author(s):  
Nick S. R. Lan ◽  
Lan T. Nguyen ◽  
Samuel D. Vasikaran ◽  
Catherine Wilson ◽  
Jacqueline Jonsson ◽  
...  
Keyword(s):  
Renal Failure ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Biological Variation ◽  
Healthy Individuals ◽  
Short Term ◽  
End Stage Renal Failure ◽  
Short And Long Term ◽  
End Stage

AbstractObjectivesHigh-sensitivity (hs) cardiac troponin (cTn) assays can quantitate small fluctuations in cTn concentration. Determining biological variation allows calculation of reference change values (RCV), to define significant changes. We assessed the short- and long-term biological variation of cardiac troponin I (cTnI) in healthy individuals and patients with renal failure requiring haemodialysis or cardiomyopathy.MethodsPlasma samples were collected hourly for 4 h and weekly for seven further weeks from 20 healthy individuals, 9 renal failure patients and 20 cardiomyopathy patients. Pre- and post-haemodialysis samples were collected weekly for 7 weeks. Samples were analysed using a hs-cTnI assay (Abbott Alinity ci-series). Within-subject biological variation (CVI), analytical variation (CVA) and between-subject biological variation (CVG) was used to calculate RCVs and index of individuality (II).ResultsFor healthy individuals, CVI, CVA, CVG, RCV and II values were 8.8, 14.0, 43.1, 45.8% and 0.38 respectively for short-term, and 41.4, 14.0, 25.8, 121.0% and 1.69 for long-term. For renal failure patients, these were 2.6, 5.8, 50.5, 17.6% and 0.30 respectively for short-term, and 19.1, 5.8, 11.2, 55.2% and 1.78 for long-term. For cardiomyopathy patients, these were 4.2, 10.0, 65.9, 30.0% and 0.16 respectively for short-term, and 17.5, 10.0, 63.1, 55.8% and 0.32 for long-term. Mean cTnI concentration was lower post-haemodialysis (15.2 vs. 17.8 ng/L, p < 0.0001), with a 16.9% mean relative change.ConclusionsThe biological variation of cTnI is similar between end-stage renal failure and cardiomyopathy patients, but proportionately greater in well-selected healthy individuals with very low baseline cTnI concentrations.

scholarly journals Short- and Long-term Biologic Variability of Galectin-3 and Other Cardiac Biomarkers in Patients with Stable Heart Failure and Healthy Adults

2016 ◽  
Vol 62 (2) ◽  
pp. 360-366 ◽  
Author(s):  
Emily I Schindler ◽  
Jeffrey J Szymanski ◽  
Karl G Hock ◽  
Edward M Geltman ◽  
Mitchell G Scott
Keyword(s):  
Heart Failure ◽  
Troponin I ◽  
Prognostic Biomarker ◽  
High Sensitivity ◽  
Cardiac Biomarkers ◽  
Healthy Individuals ◽  
Short Term ◽  
Galectin 3 ◽  
Short And Long Term

Abstract BACKGROUND Galectin-3 (Gal-3) has been suggested as a prognostic biomarker in heart failure (HF) patients that may better reflect disease progression than traditional markers, including B-type natriuretic peptide (BNP) and cardiac troponins. To fully establish the utility of any biomarker in HF, its biologic variability must be characterized. METHODS To assess biologic variability, 59 patients were prospectively recruited, including 23 male and 16 female patients with stable HF and 10 male and 10 female healthy individuals. Gal-3, BNP, and high-sensitivity cardiac troponin I (hs-cTnI) were assayed at 5 time points within a 3-week period to assess short-term biologic variability. Long-term (3-month) biologic variability was assessed with samples collected at enrollment and after 4, 8, and 12 weeks. RESULTS Among healthy individuals, mean short-term biologic variability, expressed as intraindividual CV (CVI), was 4.5% for Gal-3, 29.0% for BNP, and 14.5% for hs-cTnI; long-term biologic variability was 5.5% for Gal-3, 34.7% for BNP, and 14.7% for hs-cTnI. In stable HF patients, mean short-term biologic variability was 7.1% for Gal-3, 22.5% for BNP, and 8.5% for hs-cTnI, and mean long-term biologic variability was 7.7% for Gal-3, 27.6% for BNP, and 9.6% for hs-cTnI. CONCLUSIONS The finding that Gal-3 has minimal intraindividual biological variability adds to its potential as a useful biomarker in HF patients.

Annual biological variation and personalized reference intervals of clinical chemistry and hematology analytes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shuo Wang ◽  
Min Zhao ◽  
Zihan Su ◽  
Runqing Mu
Keyword(s):  
Clinical Chemistry ◽  
Population Based ◽  
Reference Intervals ◽  
Biological Variation ◽  
Annual Data ◽  
Healthy Individuals ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Personalized Diagnosis

Abstract Objectives A large number of people undergo annual health checkup but accurate laboratory criterion for evaluating their health status is limited. The present study determined annual biological variation (BV) and derived parameters of common laboratory analytes in order to accurately evaluate the test results of the annual healthcare population. Methods A total of 43 healthy individuals who had regular healthcare once a year for six consecutive years, were enrolled using physical, electrocardiogram, ultrasonography and laboratory. The annual BV data and derived parameters, such as reference change value (RCV) and index of individuality (II) were calculated and compared with weekly data. We used annual BV and homeostatic set point to calculate personalized reference intervals (RIper) which were compared with population-based reference intervals (RIpop). Results We have established the annual within-subject BV (CVI), RCV, II, RIper of 24 commonly used clinical chemistry and hematology analytes for healthy individuals. Among the 18 comparable measurands, CVI estimates of annual data for 11 measurands were significantly higher than the weekly data. Approximately 50% measurands of II were <0.6, the utility of their RIpop were limited. The distribution range of RIper for most measurands only copied small part of RIpop with reference range index for 8 measurands <0.5. Conclusions Compared with weekly BV, for annual healthcare individuals, annual BV and related parameters can provide more accurate evaluation of laboratory results. RIper based on long-term BV data is very valuable for “personalized” diagnosis on annual health assessments.

Biological variation in analyte concentrations in urine of apparently healthy men and women.

1987 ◽  
Vol 33 (6) ◽  
pp. 847-850 ◽  
Author(s):  
E M Gowans ◽  
C G Fraser
Keyword(s):  
Reference Values ◽  
Interindividual Variation ◽  
Healthy Individuals ◽  
Sodium Potassium ◽  
Men And Women ◽  
Mean Values ◽  
Urine Creatinine ◽  
Sodium And Potassium ◽  
Urine Specimens ◽  
Apparently Healthy

Abstract Analytical, intra-individual, and interindividual components of variation for sodium, potassium, urea, creatinine, calcium, and phosphate were estimated from results for 24-h urine specimens collected from 15 apparently healthy individuals every four weeks for 40 weeks. Expressed as output, mean values differed for men and women, except for calcium. Our data on intra-individual variation were similar to those obtained for 10 men by Shephard et al. (Clin Chem 1981;27:569-73). Calculated analytical goals are easily attained by current methods. Reference values for urine creatinine are useful only when expressed as output and stratified according to gender. The ratios of intra- to interindividual variation generally increase on such stratification; separate reference values for men and women are therefore required for analytes expressed as output. Measurements of sodium and potassium in urine should be reported as concentration, but output terms are favored for the other analytes. Differences for two serial results from an individual must be rather large to differ statistically.

scholarly journals Short- and Long-Term Biological Variation in Cardiac Troponin I Measured with a High-Sensitivity Assay: Implications for Clinical Practice

2009 ◽  
Vol 55 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Alan H B Wu ◽  
Quynh Anh Lu ◽  
John Todd ◽  
Joachim Moecks ◽  
Frank Wians
Keyword(s):  
Detection Limit ◽  
Cardiac Troponin ◽  
Troponin I ◽  
High Sensitivity ◽  
Population Based ◽  
Biological Variation ◽  
Cardiac Troponin I ◽  
Low Concentrations ◽  
Short And Long Term

Abstract Background: The improved detection limit and precision in new-generation commercial assays for cardiac troponin I (cTnI) have lowered the 99th-percentile cutoff value, yielding higher frequencies of positive test results. Because serial testing is important in interpreting low concentrations, we evaluated the biological variation of cTnI in both the short (hours) and long (weeks) terms and determined reference change values (RCVs) and the index of individuality (II) for cTnI. Methods: To assess short- and long-term variation, we collected blood from 12 healthy volunteers hourly for 4 h and from 17 healthy individuals once every other week for 8 weeks, measured cTnI with a high-sensitivity assay (detection limit, 0.2 ng/L), and computed analytical, intraindividual, interindividual, and total CVs (CVA, CVI, CVG, and CVT, respectively; CVT = CVA + CVI + CVG) as well as the II. Because of the slight right-skewness of the data, RCVs were calculated with a lognormal approach. Results: Within-day CVA, CVI, and CVG values were 8.3%, 9.7%, and 57%, respectively; the corresponding between-day values were 15%, 14%, and 63%. Within- and between-day IIs were 0.21 and 0.39, respectively. Lognormal within-day RCVs were 46% and −32%, respectively; the corresponding between-day values were 81% and −45%. Conclusions: The low II indicates that population-based reference intervals are less useful for interpreting cTnI values than following serial changes in values in individual patients. This criterion is particularly important for interpreting results from patients who show cTnI increases at low concentrations measured with very high-sensitivity assays, from patients presenting with chest pain (short term), and for evaluating drugs for cardiotoxicity (long term).

Biological variation of serum neurofilament light chain

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Claus Vinter Bødker Hviid ◽  
Anne Tranberg Madsen ◽  
Anne Winther-Larsen
Keyword(s):  
Light Chain ◽  
Reference Intervals ◽  
Biological Variation ◽  
Healthy Individuals ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
Linear Mixed Effects ◽  
Serial Measurements ◽  
Analytical Variation ◽  
Apparently Healthy

Abstract Objectives The neurofilament light chain (NfL) has emerged as a versatile biomarker for CNS-diseases and is approaching clinical use. The observed changes in NfL levels are frequently of limited magnitude and in order to make clinical decisions based on NfL measurements, it is essential that biological variation is not confused with clinically relevant changes. The present study was designed to evaluate the biological variation of serum NfL. Methods Apparently healthy individuals (n=33) were submitted to blood draws for three days in a row. On the second day, blood draws were performed every third hour for 12 h. NfL was quantified in serum using the Simoa™ HD-1 platform. The within-subject variation (CVI) and between-subject variation (CVG) were calculated using linear mixed-effects models. Results The overall median value of NfL was 6.3 pg/mL (range 2.1–19.1). The CVI was 3.1% and the CVG was 35.6%. An increase in two serial measurements had to exceed 24.3% to be classified as significant at the 95% confidence level. Serum NfL levels remained stable during the day (p=0.40), whereas a minute variation (6.0–6.6 pg/mL) was observed from day-to-day (p=0.02). Conclusions Serum NfL is subject to tight homeostatic regulation with none or neglectable semidiurnal and day-to-day variation, but considerable between-subject variation exists. This emphasizes serum NfL as a well-suited biomarker for disease monitoring, but warrants caution when interpreting NfL levels in relation to reference intervals in a diagnosis setting. Furthermore, NfL’s tight regulation requires that the analytical variation is kept at a minimum.

scholarly journals Short- and Long-Term Exposure to Particulate Matter and Pulse Wave Velocity

2021 ◽  
Vol 42 (4) ◽  
pp. 310-316
Author(s):  
Young Jun Park ◽  
Yu Jin Cho ◽  
Jinseul Kwak ◽  
Youn-Hee Lim ◽  
Minseon Park
Keyword(s):  
Particulate Matter ◽  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Short Term ◽  
Obese Subjects ◽  
Short And Long Term ◽  
Pm10 Exposure ◽  
Apparently Healthy

Background: In hemodialysis patients, brachial-ankle pulse wave velocity (baPWV) levels are affected by particulate matter with an aerodynamic diameter of 10 μm or less (PM10). We conducted this study to determine whether there is an association between short- and long-term PM10 exposure and baPWV in apparently healthy adults aged 40 years and older.Methods: A total of 1,628 subjects who underwent health examinations between 2006 and 2009 were included in the study. On the basis of the day of medical screening, the 1–3-day and 365-day moving averages of PM10 concentrations were used to evaluate the association between short- and long-term exposure to PM10 and high baPWV (≥the third quartile of baPWV, 1,534 cm/s) using logistic regression models. Additional subgroup analyses were conducted according to age, sex, obesity (body mass index ≥25.0 kg/m2), and comorbidities such as metabolic syndrome.Results: No statistically significant associations were identified between short-term and long-term exposure to PM10 and baPWV in any of the subjects and subgroups. A 10-μg/m3 increase in the 2-day moving average of PM10 exposure was marginally associated with high baPWV in non-obese subjects (odds ratio, 1.059; P=0.058). This association in non-obese subjects was significantly different from that in obese subjects (P=0.038).Conclusion: This study did not show statistically significant associations between short-term and long-term exposure to PM10 and baPWV in apparently healthy subjects. With short-term exposure to PM10, non-obese subjects showed a marginally unfavorable association with baPWV. Further studies are necessary to validate and elucidate the mechanism underlying the effect of PM10 on baPWV.

Biological variation in urine samples used for analyte measurements

1994 ◽  
Vol 40 (3) ◽  
pp. 472-477 ◽  
Author(s):  
C Ricós ◽  
C V Jiménez ◽  
A Hernández ◽  
M Simón ◽  
C Perich ◽  
...  
Keyword(s):  
Biological Variation ◽  
Urine Samples ◽  
Healthy Individuals ◽  
Urine Creatinine ◽  
Specimen Collection ◽  
Different Types ◽  
Insight Into ◽  
Urine Specimens

Abstract To determine the influence of biological variation on the reliability of data from different types of urine specimens, we measured nine analytes in first-morning, randomly collected, and 24-h samples of urine from 53 healthy individuals (14 men and 39 women). The urines were collected once a week for 10 weeks. The data obtained were used as a basis for specimen collection and to gain insight into the influence of urine quantities in the diagnosis, screening, and monitoring of patients. We found that 24-h urine expressed in output rather than concentration units is the most reliable specimen for diagnosis and monitoring for most of the analytes studied. On the basis of the ratio between estimated within- and between-subject variation, the tests with greatest medical usefulness for diagnosis and screening of specific pathologies are those measuring protein and sodium. Moreover, the results indicate that urine creatinine may be a poor test for diagnosis, monitoring, and screening.

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