scholarly journals Variability in the measurement of C-reactive protein in healthy subjects: implications for reference intervals and epidemiological applications

1997 ◽  
Vol 43 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Elizabeth M Macy ◽  
Timothy E Hayes ◽  
Russell P Tracy
Keyword(s):  
Clinical Chemistry ◽  
Reference Interval ◽  
Reference Intervals ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Analytical Variability ◽  
Subject Variability ◽  
Donor Population ◽  
Index Of Individuality ◽  
Small Index

Abstract We developed a reproducible ELISA for C-reactive protein (CRP), calibrated with WHO Reference Material, for which intra- and interassay CVs were 3.0% and 6.0%, respectively. Analytical recovery was 97.9%. The distribution of CRP in a healthy blood donor population (n = 143) was nongaussian, with 2.5th, 50th, and 97.5th percentile values of 0.08, 0.64, and 3.11 mg/L, respectively. There was no sex-related difference, and the association with age was weak. In a study of variability [by the method of Fraser and Harris (Crit Rev Clin Lab Sci 1989;27:409–37)], the analytical variability was 5.2%; the within-subject variability, CVI, was 42.2%; and the between-subject variability, CVG, was 92.5%. The critical difference for sequential values significant at P ≤0.05 (i.e., the smallest percentage change unlikely to be due to analytical variability or CVI) was calculated as 118%, and the index of individuality, CVI/CVG, was 0.46. This suggests that CRP, like many clinical chemistry analytes, has limited usefulness in detecting early disease-associated changes when used in conjunction with a healthy reference interval. From a molecular epidemiological standpoint, the usefulness of CRP in longitudinal studies is suggested by the small index of individuality and by observations that (a) short-term fluctuations were infrequent, (b) all data stayed within the reference interval, and (c) relative rankings of the subjects over 6 months only moderately deteriorated.

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.

Reference intervals for procalcitonin and C-reactive protein after major abdominal surgery

2002 ◽  
Vol 62 (3) ◽  
pp. 189-194 ◽  
Author(s):  
M. Lindberg ◽  
A. Åsberg ◽  
H. E. Myrvold ◽  
A. Hole ◽  
A. Rydning ◽  
...  
Keyword(s):  
Abdominal Surgery ◽  
Reference Intervals ◽  
Major Abdominal Surgery ◽  
C Reactive Protein ◽  
Reactive Protein

scholarly journals Personalized Reference Intervals in Laboratory Medicine: A New Model Based on Within-Subject Biological Variation

2020 ◽  
Author(s):  
Abdurrahman Coşkun ◽  
Sverre Sandberg ◽  
Ibrahim Unsal ◽  
Coskun Cavusoglu ◽  
Mustafa Serteser ◽  
...  
Keyword(s):  
Steady State ◽  
Personalized Medicine ◽  
Clinical Chemistry ◽  
Reference Interval ◽  
Reference Intervals ◽  
Biological Variation ◽  
Test Results ◽  
Steady State Condition ◽  
Laboratory Test Results ◽  
Measurement Results

Abstract Background The concept of personalized medicine has received widespread attention in the last decade. However, personalized medicine depends on correct diagnosis and monitoring of patients, for which personalized reference intervals for laboratory tests may be beneficial. In this study, we propose a simple model to generate personalized reference intervals based on historical, previously analyzed results, and data on analytical and within-subject biological variation. Methods A model using estimates of analytical and within-subject biological variation and previous test results was developed. We modeled the effect of adding an increasing number of measurement results on the estimation of the personal reference interval. We then used laboratory test results from 784 adult patients (&gt;18 years) considered to be in a steady-state condition to calculate personalized reference intervals for 27 commonly requested clinical chemistry and hematology measurands. Results Increasing the number of measurements had little impact on the total variation around the true homeostatic set point and using ≥3 previous measurement results delivered robust personalized reference intervals. The personalized reference intervals of the study participants were different from one another and, as expected, located within the common reference interval. However, in general they made up only a small proportion of the population-based reference interval. Conclusions Our study shows that, if using results from patients in steady state, only a few previous test results and reliable estimates of within-subject biological variation are required to calculate personalized reference intervals. This may be highly valuable for diagnosing patients as well as for follow-up and treatment.

Reference intervals for 21 clinical chemistry analytes in arterial and venous umbilical cord blood

1993 ◽  
Vol 39 (6) ◽  
pp. 1041-1044 ◽  
Author(s):  
S L Perkins ◽  
J F Livesey ◽  
J Belcher
Keyword(s):  
Alkaline Phosphatase ◽  
Umbilical Cord ◽  
Clinical Chemistry ◽  
Venous Blood ◽  
Reference Interval ◽  
Reference Intervals ◽  
Nonparametric Analysis ◽  
Term Infants ◽  
Male And Female ◽  
Gamma Glutamyltransferase

Abstract Reference intervals were determined for 21 clinical chemistry analytes in umbilical cord arterial and venous blood from healthy term infants. Nonparametric analysis (rank number) was used to determine the central 95% reference interval. No significant differences were observed between male and female infants. Reference intervals for glucose, urea, creatinine, urate, phosphate, calcium, albumin, total protein, cholesterol, triglycerides, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, gamma-glutamyltransferase, and magnesium all were significantly different from adult values.

scholarly journals Serial Measurements of C-Reactive Protein and Interleukin-6 in the Immediate Postnatal Period: Reference Intervals and Analysis of Maternal and Perinatal Confounders

2001 ◽  
Vol 47 (6) ◽  
pp. 1016-1022 ◽  
Author(s):  
Claudio Chiesa ◽  
Fabrizio Signore ◽  
Marcello Assumma ◽  
Elsa Buffone ◽  
Paola Tramontozzi ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Early Onset ◽  
Gestational Hypertension ◽  
Neonatal Infection ◽  
Reference Intervals ◽  
Postnatal Period ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Wide Range ◽  
Near Term

Abstract Background: There is a wide range of reported sensitivities and specificities for C-reactive protein (CRP) and interleukin-6 (IL-6) in the detection of early-onset neonatal infection. This prompted us to assess reference intervals for CRP and IL-6 during the 48-h period immediately after birth and to identify maternal and perinatal factors that may affect them. Methods: CRP and IL-6 values were prospectively obtained for 148 healthy babies (113 term, 35 near-term) at birth and at 24 and 48 h of life, and from their mothers at delivery. Results: Upper reference limits for CRP at each neonatal age were established. At birth, CRP was significantly lower than at 24 and 48 h of life. Rupture of membranes ≥18 h, perinatal distress, and gestational hypertension significantly affected the neonatal CRP dynamics, but at specific ages. There was no correlation between CRP concentrations in mothers and their offspring at birth. The IL-6 values observed in the delivering mothers and in their babies at all three neonatal ages were negatively associated with gestational age. In the immediate postnatal period, IL-6 dynamics for term babies were significantly different from those for near-term babies. Maternal IL-6 concentrations correlated with babies’ IL-6 concentrations only for term deliveries. Apgar score had a significant effect on babies’ IL-6 values at birth. Conclusions: The patterns of CRP and IL-6 responses in the healthy neonate should be taken into account to optimize their use in the diagnosis of early-onset neonatal sepsis.

scholarly journals C-Reactive Protein and Lymphocyte are important indicators of severe coronavirus disease and poor prognosis in elderly patients

2020 ◽  
Author(s):  
Qinglin He ◽  
Xiafen Hu ◽  
Xiaochen Xiang ◽  
Siyang Chen ◽  
Wanxin Liu ◽  
...  
Keyword(s):  
Elderly Patients ◽  
Disease Severity ◽  
Area Under The Curve ◽  
Reference Interval ◽  
The Elderly ◽  
C Reactive Protein ◽  
Roc Curve Analysis ◽  
Dynamic Changes ◽  
Reactive Protein ◽  
Risk Of Death

Abstract Objective：To explore the value of C-reactive protein (CRP) and lymphocyte (L) in the assessment of disease severity and prognosis of elderly COVID-19 patients.Methods: A total of 194 positive COVID-19 patients were collected from Tianyou Hospital and Puren Hospital, affiliated hospital of Wuhan University of Science and Technology. Their demographic characteristics were analyzed. The dynamic changes of CRP and L in peripheral blood were retrospectively studied.Results: (1) There were significant statistical differences in CRP, L in clinical typing and clinical outcome in patients over 60 years old compared with those under 60 years old. Survival analysis showed that the risk of death was greater in patients over 60 than in those under 60.（2）In 125 patients over 60 years old, the hospitalized patients with severe or critical types of disease had significantly higher CRP than those with moderate type (p<0.01). In the outcome of the elderly patients, the CRP of the patients with the outcomes of discharge, improvement, aggravation and death increased successively (p<0.01). According to the analysis of Logistic regression model, the increase of CRP constitutes a risk factor for death in elderly patients. (3) In the ROC curve analysis to distinguish the death outcome and non-death outcome of COVID-19 patients, the area under the curve (AUC) of CRP and L was 0.751 and 0.720 respectively. CRP and L had good diagnostic accuracy for the death outcome of patients. (4) Changes in CRP were correlated with changes in CT imaging and were consistent with changes in the course of the disease.Conclusions: (1) The data collected in this research showed that the cumulative survival rate of patients over 60 years old was lower than that of patients under 60 years old. With the increase of age, the CRP of patients showed an increasing trend, and the L of patients showed a characteristic lower than the normal reference interval. (2) CRP and L are important monitoring indicators of COVID-19 in elderly patients. Combined with CT examination and observation of their dynamic changes, CRP and L are of important clinical guiding value for the judgment of disease severity and the evaluation of prognosis.

Development and performance of a fully automated method for assay of C-reactive protein in the aca discrete clinical analyzer.

1988 ◽  
Vol 34 (8) ◽  
pp. 1646-1649 ◽  
Author(s):  
M W Schwartz ◽  
R S Schifreen ◽  
E Gorman ◽  
P M Tuhy ◽  
J Bienvenu ◽  
...  
Keyword(s):  
Emergency Room ◽  
Rheumatoid Factor ◽  
Total Bilirubin ◽  
Reference Interval ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Automated Method ◽  
Quantitative Immunoassay ◽  
And Performance ◽  
Turbidimetric Immunoassay

Abstract A quantitative immunoassay for C-reactive protein (CRP) has been developed for use in the Du Pont aca discrete clinical analyzer. Particle-enhanced turbidimetric immunoassay (PE-TIA) technology is used. The method has a CV of less than 10% in the range 2 to 120 mg/L. Neither hemolyzed samples (Hb less than 5 g/L), icteric samples (total bilirubin less than 300 mg/L), lipemic samples (triglyceride less than 15 g/L), nor some commonly used drugs interfere. Dithioerythritol is used to eliminate interference from rheumatoid factor. Good correlation was seen when the Du Pont CRP method was compared with the Beckman ICS, Syva EMIT, TDx, and Behring methods for CRP. The normal reference interval is 0 to 9 mg/L. The method, which is fully automated, is fast, requires only a few microliters of serum, and is well suited to emergency-room requirements.

scholarly journals The Influence of a Health-Related Fitness Training Program on Motor Performance as Well as Hematological and Biochemical Parameters

2020 ◽  
Vol 17 (2) ◽  
pp. 578
Author(s):  
Dorota Kostrzewa-Nowak ◽  
Anna Nowakowska ◽  
Teresa Zwierko ◽  
Maciej Rybak ◽  
Robert Nowak
Keyword(s):  
Training Program ◽  
General Health ◽  
Motor Performance ◽  
Clinical Chemistry ◽  
Exercise Program ◽  
C Reactive Protein ◽  
Enzymes Activities ◽  
Protein Levels ◽  
Reactive Protein ◽  
Before And After

The study was aimed at designing a health exercise program appealing to inactive young men, and then testing the men’s metabolic responses to the program using common diagnostic markers of general health. Six men, aged 22–29 years, took a part in training program to increase their motor performance and improve general health conditions. Body composition parameters, clinical chemistry variables (metabolites, albumin, total protein, ferritin, C reactive protein, lipid profile, ions, and selected enzymes activities) and blood morphology parameters were determined. Motor performance measured before and after a 4-month-long macrocycle indicated an increase in endurance, pace, and agility of the participants. Significant differences were found in analyzed enzymes activities. There was a significant increase in C-reactive protein levels from pre- to post-training. Additionally, changes in hematological biomarkers were seen that suggest erythropoiesis might significantly increase, specifically during the last 2-month-long mesocycles. The proposed training program induced small improvements in endurance, pace, and agility. It was also confirmed that changes in aspartate (AST) and alanine (ALT) activities emerge before any increase in creatine kinase (CK) activity that is important in monitoring of the training loads. Observed changes in red blood cell-related parameters suggest increase in erythropoiesis in the second half of the training cycle.

C-reactive protein as a marker of cardiovascular disease in patients with a schizophrenia spectrum disorder treated in routine medical practice

2011 ◽  
Vol 28 (3) ◽  
pp. 161-167 ◽  
Author(s):  
A. Sicras-Mainar ◽  
J. Rejas-Gutiérrez ◽  
R. Navarro-Artieda ◽  
M. Blanca-Tamayo
Keyword(s):  
Clinical Chemistry ◽  
Spectrum Disorder ◽  
Administrative Claims ◽  
C Reactive Protein ◽  
Cvd Risk ◽  
Schizophrenia Spectrum Disorder ◽  
Cross Sectional ◽  
Reactive Protein ◽  
Schizophrenia Spectrum ◽  
Very High

AbstractObjectiveInterest in cardiovascular diseases (CVD) in schizophrenia has grown recently due to documented incremental mortality. C-reactive protein (CRP) has been assessed as a marker in individuals with CVD and/or at high risk of developing it. However, its role in schizophrenia patients is unknown. The goal of this research was thus to explore the use of CRP as a marker of CVD risk in patients with schizophrenia.MethodsA cross-sectional analysis of the Badalona Serveis Assistencials (BSA) administrative claims database was conducted including all subjects aged > 18 years with a diagnosis of schizophrenia spectrum disorder. CRP measurement, sociodemographics, medical history, 10-year CVD risk (Framingham function) and clinical chemistry data were extracted for analysis.ResultsSeven hundred and five patients (53.0% men, 48.2 [15.8] years, 78.7% on atypicals) met criteria for analysis. Mean 10-year CVD risk was high; 11.9 ± 5.7% and mean CRP levels were 2.6 ± 2.5 mg/L with 30.4% showing above-normative levels (> 3 mg/L). After adjusting for age, gender, smoking and presence of neoplasm or inflammatory diseases, CRP was linearly associated with 10-year CVD risk stratified by risk (low, moderate, high/very high): respectively, 2.3 (95% CI: 2.1–2.5), 3.1 (2.6–3.5) and 3.7 (3.2–4.1) mg/L; F = 13.5, P < 0.001. Patients with known CVD also showed higher CRP levels: 3.7 (2.9–4.5) vs. 2.5 (2.4–2.7) mg/L, P = 0.008; and higher probability of above-normal values; odds ratio = 4.71 (2.01–11.04), P < 0.001.ConclusionsHigh CRP levels above normative were associated with both known CVD and high/very high 10-year risk of a CVD event in patients with schizophrenia, suggesting CRP could be a marker of CVD in this psychiatric disorder.

scholarly journals Indirect methods for reference interval determination – review and recommendations

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Graham R.D. Jones ◽  
Rainer Haeckel ◽  
Tze Ping Loh ◽  
Ken Sikaris ◽  
Thomas Streichert ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Direct Methods ◽  
Analytical Techniques ◽  
Reference Interval ◽  
Reference Population ◽  
Reference Intervals ◽  
Statistical Techniques ◽  
Indirect Methods ◽  
Indirect Approach ◽  
Patient Health

Abstract Reference intervals are a vital part of the information supplied by clinical laboratories to support interpretation of numerical pathology results such as are produced in clinical chemistry and hematology laboratories. The traditional method for establishing reference intervals, known as the direct approach, is based on collecting samples from members of a preselected reference population, making the measurements and then determining the intervals. An alternative approach is to perform analysis of results generated as part of routine pathology testing and using appropriate statistical techniques to determine reference intervals. This is known as the indirect approach. This paper from a working group of the International Federation of Clinical Chemistry (IFCC) Committee on Reference Intervals and Decision Limits (C-RIDL) aims to summarize current thinking on indirect approaches to reference intervals. The indirect approach has some major potential advantages compared with direct methods. The processes are faster, cheaper and do not involve patient inconvenience, discomfort or the risks associated with generating new patient health information. Indirect methods also use the same preanalytical and analytical techniques used for patient management and can provide very large numbers for assessment. Limitations to the indirect methods include possible effects of diseased subpopulations on the derived interval. The IFCC C-RIDL aims to encourage the use of indirect methods to establish and verify reference intervals, to promote publication of such intervals with clear explanation of the process used and also to support the development of improved statistical techniques for these studies.

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