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PubMed2004

Reference values for cardiac troponins I and T in a goal-oriented concept of health: cardiac marker values in a series of outpatients without acute coronary syndromes.

BACKGROUND: Cardiac troponins are part of the new definition of acute myocardial infarction (AMI) by the European Society of Cardiology and the American College of Cardiology (ESC/ACC). In the new guidelines, it was suggested to establish reference values for cardiac troponins to calculate the 0.99 quantile (Q99) as cutoff for AMI diagnosis. PATIENTS AND METHODS: We run a prospective series of troponin measurements in unselected outpatients who had no suspicion of cardiac ischemia. The selection of patients as reference population is based on a "goal-oriented concept of health". One hundred and ninety-five patients agreed that 10-ml additional blood was drawn at the occasion of the venous puncture done routinely in the evaluation of their case. Cardiac troponin I was measured using a point of care (POCT) device (Stratus CS, DadeBehring, TNI-PO). Additionally, heparin-plasma was obtained and immediately deep-frozen to -80 degrees C for later batch measurement of cardiac troponin T (Elecsys 2010, Roche Diagnostics, TnT) and troponin I (Centaur, Bayer, TnI-CL). RESULTS: The Q99 values were 0.14 microg/l for TnI-PO, 0.023 microg/l for TnT and 0.07 microg/l for TnI-CL in patients with creatinine levels below 1.5 mg/dl. These values lay above those obtained from people at good health for reference study purposes. On the level of our cutoffs, CVs were 7.5%, 6.4% and 23.7% for TnI-PO, TnT and TnI-CL, respectively. CONCLUSIONS: Only the TnI-PO and TnT tests fulfilled the imprecision criteria in our study. TnI-PO values between 0.10 and 0.14 microg/l and TnT values between 0.01 and 0.03 microg/l have to be interpreted carefully. Patients presenting with chest pain will be possibly true positives, but patients without chest pain and nondiagnostic ECGs should be subjected to repetitive troponin measurements and further noninvasive investigation and maybe not directly sent to the cardiac catheter laboratory.

Adult↗

PubMed1981

Xanthurenic acid excretion in urine after oral intake of 5 grams L-tryptophan by healthy volunteers: standardisation of the reference values.

The excretion of xanthurenic acid in urine after oral intake of 5 grams of L-tryptophan was studied and correlated with test and test-person parameters. The xanthurenic acid was determined by a colorimetric method, which gives reliable and reproducible results. Two groups, of 11 healthy volunteers each, participated. The first group started the test at 08.00 hours and the second group at 22.00 hours. Both groups repeated the same test, within one weed of the first test, at 22.00 hours. The xanthurenic acid excretion in the 24-hour urine correlated significantly (p = 0.04) with urine volume, but did not correlated with age, sex, height, body-weight, urine pH and urinary output of creatinine or 17-hydroxysteroids. The intraindividual variability of the test is not significant. The test should be started in the evening and the urine should be collected over 24 hours. The new reference values for the xar thurenic acid excretion under these conditions are 68.8 +/- 19.0 mumols/24 h.

Aging↗

PubMed1995

Experimental models, protocols, and reference values for evaluation of iodinated analogues of glucose.

For an iodinated analogue of glucose to be useful for evaluating glucose uptake using single-photon emission computed tomography (SPECT), it must enter the cell via the same transporter as glucose and accumulate within the cell without being degraded. The biological behavior of the iodinated tracer must therefore be similar to that of 2-deoxy-D(-)[1-14C]-glucose (2-DG). In the present study, four experimental models (biodistribution in mouse, isolated rat heart, human erythrocytes in suspension and cultured neonatal rat cardiomyocytes) have been chosen and protocols have been set up which allow for the examination of small quantities of iodinated analogues of glucose. The uptakes of 2-DG and of L(-)[1-14C]-glucose have been measured in these models to establish reference values which will be compared with uptake values for iodinated analogues of glucose.

Animals↗

PubMed2001

Combined body plethysmographic, spirometric and flow volume reference values for male and female children aged 6 to 16 years obtained from "hospital normals".

UNLABELLED: Vital capacity (VC) and its subdivisions (IC and ERV), total lung capacity (TLC), residual volume (RV), peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum flow volume curve (MEF75, MEF50, MEF25, MMEF, FEF75-85), airway resistance (Rtot, Reff) and the thoracic gas volume at resting expiratory position (FRC) were measured in 187 girls and 213 boys (hospital normals) aged 6 to 16 years. The measurements were carried out consecutively on the same subjects in the morning using a volume-constant plethysmograph (Master-Lab, E. Jaeger; programs: body plethysmography, spirometry and flow volume). Using multiple regression analysis the best fitting curves for the prediction of normal values for boys and girls were selected. Analyses of covariance were performed to compare the adjusted means of the spirometric and body plethysmographic variables of the male and female subjects. As expected, we found higher static and dynamic (FVC, FEV1, PEF) lung volumes in boys than in girls relating to height. The flows (MMEF, MEF50, MEF25, FEF75-85) were significantly lower in the male than in the female subjects of the same age justifying separate prediction equations, but the same equation for both genders may be used for the resistance variables Rtot and Reff. Our results are compared with those of previous studies. CONCLUSION: Lung volumes and flows differ significantly between girls and boys calling for separate reference values for female and male subjects of the same age.

Adolescent↗

PubMed1999

Reference values of urinary excretion of cystine and dibasic aminoacids: classification of patients with cystinuria in the Valencian Community, Spain.

OBJECTIVE: Cystinuria is an autosomal-recessive disorder of the kidneys and small intestine affecting a luminal transport mechanism shared by cystine, ornithine, arginine, and lysine. Three different types of cystinuria can be distinguished according to the excretion of these amino acids in urine samples. We propose cutoff values from our population as references and we present a classification of cystinuric patients using quantitative amino acid chromatography in first morning urine samples. DESIGN AND METHODS: A random sample of forty healthy subjects belonging to general population of the Valencian Community were selected as control subjects. Cystine, lysine, arginine, and ornithine were quantified by reverse-phase HPLC. Seventy-two subjects, diagnosed previously as cystinuric by the cyanide-nitroprusside test were classified. Probands excreting more than 113.12 micromol cystine per mmol of creatinine (i.e., 1,000 micromol cystine per gram of creatinine) were classified as homozygotes. Parents of homozygotes in whom excretion of amino acids were normal were classified as heterozygotes type I. Those probands showing the excretion of at least one amino acid and the sum of urinary cystine plus the basic amino acids higher than the corresponding references ranges in our population were classified as heterozygotes type II or type III (heterozygotes non-type 1). RESULTS: We identified 24 homozygotes, 39 non-type I heterozygotes and 3 type I heterozygotes. The remaining 6 probands could not be classified. Means for cystine, lysine, arginine ornithine and their sum in homozygotes and heterozygotes non-type I were significantly (p < 0.001) in excess of the respective reference ranges. Moreover, means values in homozygotes were statistically different (p < 0.001) from heterozygotes non-type I. CONCLUSION: Urinary excretion of cystine per mmol creatinine allow us to distinguish heterozygotes from homozygotes. However, the best discriminator to distinguish non-type I heterozygotes from normal population might be the excretion of lysine per mmol creatinine. Additional studies including characterization of appropriate haplotypes should be carried out for a more precise identification of types of cystinuria.

Adolescent↗

PubMed1989

Spirometric reference values in Senegalese black adults.

Spirometric volumes and expiratory flows were measured among 448 Senegalese males and females of 25-80 yrs of age. The values obtained are similar to those reported for black Africans and black Americans in the literature. Volumes are 15-25% lower in males and 23% lower in females than in Caucasians. Forced expiratory flow between 25-75% of vital capacity (VC), (FEF25-75) is 5-18% lower in males and 19% lower in females. FEF25-75/VC ratio is higher in blacks than in Whites, but the forced expiratory volume in one second FEV1/VC ratio is similar in black and white subjects. However, we cannot use proportional factors to determine spirometric black standards from white reference values, so, equations of regression and nomograms with age and height are proposed for black Africans.

Adult↗

PubMed1993

Reference values for vertebral heights in Scandinavian females and males.

Vertebral heights were measured on lateral spine radiographs covering T4-L5 in 113 healthy Caucasian volunteers (73 females aged 22-80 years, and 40 males aged 22-79 years). Vertebral heights were significantly higher in men than in women (p < 0.001). In women, a significant correlation was found between the height of T4 and the heights of the other vertebrae with correlation coefficients ranging from 0.71 (T5) to 0.38 (L1) and similar figures were found in males. Both the absolute and relative vertebral heights in this series were close to those reported by others. Selection of subjects and racial, environmental, and technical factors may explain the small differences. It is concluded that vertebral heights can be predicted from vertebrae rarely affected by spinal osteoporosis. Both relative and absolute vertebral heights differed between sexes. Although the reference values in this Scandinavian population were in agreement with previously reported data, small differences between populations were found, emphasizing the need for regional normative data.

Adult↗

PubMedDate not supplied

Reference values for normal adult transesophageal echocardiographic measurements.

Normal transesophageal echocardiographic measurements have not been presented previously relative to the effects of age, sex, and body surface area. This comparison was obtained by measuring cardiac and aortic dimensions in 60 patients (20 to 75 years old; 33 women) with normal transesophageal echocardiograms. We found a variable and usually important relationship between body surface area and 11 of 20 structures measured. A gender effect was not significant after indexing for body surface area for all but one structure. Age correlated with the diameter of the aortic root, descending aorta, superior vena cava, and right pulmonary artery. Similar dimensions were noted for certain paired structures as the two atria, the mitral and tricuspid annuli, and the aortic root and right ventricular outflow tract. Although multiple factors underlie what is normal in a given individual, our reference values serve to facilitate recognition of cardiac and aortic disease.

Adult↗

PubMed2005

Reference values of NT-proBNP serum concentrations in the umbilical cord blood and in healthy neonates and children.

BACKGROUND: N-terminal brain natriuretic peptide (NT-proBNP) is a neurohormonal substance secreted mainly by the cardiac myocytes of the left ventricle and to a less degree of the left atrium. The releasing mechanism is induced by an increased wall stress on the base of volume or pressure load of the ventricle. The physiologic actions of BNP are prohibition of the sympathetic activity, vasodilatation, natriuresis, diureses and inhibition of the renin-angiotensin system. Because of its high sensitivity and specifity in relation to the left ventricular incompetence, BNP as well as NTproBNP are well accepted markers of ventricular dysfunction. It was the aim of the study to establish reference values of NT-proBNP serum concentrations throughout childhood, in particular in the newborn age group. METHODS: In a cross sectional study, serum NT-proBNP concentrations were measured by an ElectroChemiLuminescenceImmunoAssay ("ECLIA" Roche) in the umbilical cord blood of 62 healthy full-term neonates and in 222 healthy probands from birth up to the age of 18 years. RESULTS: The concentration of NT-proBNP in the cord blood samples ranged from 281 to 2595 pg/ml (mean: 818 pg/ml). There was a significant increase in the first days of life followed by a rapid decrease during the first year and a further gradual decrease throughout infancy; beyond the 10(th) year of age normal adult values were approached. CONCLUSIONS: The knowledge of the normal range of plasma NT-proBNP levels in healthy subjects during childhood serves as a non-invasive marker for differentiation of pathologic conditions such as acute myocarditis, hypertrophic or dilated cardiomyopathy, tachyarrhythmias and pulmonary hypertension.

Adolescent↗

PubMed2006

Nickel quantification in serum by a validated sector-field inductively coupled plasma mass spectrometry method: Assessment of tentative reference values for an Italian population.

The daily exposure to Ni from food, industrial processes, jewellery and coins makes the determination of Ni in human serum an important way to monitor the health status in non-occupationally exposed subjects. To this end, a method based on sector-field inductively coupled plasma mass spectrometry was developed and validated. The limits of detection (LoD) and quantification (LoQ), sensitivity, linearity range, trueness, repeatability, within-laboratory reproducibility and robustness were the considered issues of the validation process. The uncertainty associated with the measurements was also calculated, according to the Eurachem/Citac Guide. The method LoD and LoQ were 0.03 and 0.09 ng mL(-1), linearity was over two order of magnitude, trueness was -3.57%, and the repeatability and reproducibility showed relative standard deviations equal to 4.56% and 6.52%, respectively. The relative expanded uncertainty was 21.8% at the Ni levels found in the general population. The tentative reference value for serum Ni was 0.466 +/- 0.160 ng mL(-1) with a related interval between 0.226 and 1.026 ng mL(-1).

Adult↗

PubMed1999

[Investigations on the dependence of hematologic and blood chemical parameters on the age of health lambs--a contribution to the definition of reference values in sheep].

Haematological and biochemical examinations were carried out in 284 clinically healthy lambs aged from birth to nine month. The 122 male and 164 female animals belonged to the following breeds: German blackheaded mutton sheep (n = 114), Merino (n = 21), Frisian milksheep (n = 98), Texel (n = 31), Bentheimer landrace (n = 16) and Leine sheep (n = 5). The lambs were selected from a larger number of probationers by use of outlier tests. No differences were found between sexes for any of examined parameters. For the period from two to eight weeks of age breed differences could be proven for glutamate dehydrogenase and creatinin. Many parameters showed a strong dependence on the age of the lambs in a linear or polynomial function. While lymphocytes, protein, urea, creatinin, 3-hydroxybutyrate and copper increased, bilirubin, glucose, calcium, inorganic phosphate and the activities of alkaline phosphatase and gamma-glutamyl-transferase decreased with age. Body weight had no influence on any examined parameter within the age dependence. Reference values (limits) are defined for healthy lambs and for healthy ewes, summarized from former studies.

Aging↗

PubMed1987

Reference values for nickel concentrations in human tissues and bile.

Nickel concentrations in human tissues and gallbladder bile were determined by analysis of postmortem specimens from ten consecutive autopsies of adult persons. The tissue samples were collected and homogenized with precautions to avoid nickel contamination and were analyzed by electrothermal atomic absorption spectrophotometry with Zeemann background correction. In decreasing order of mean nickel concentrations, the following results were obtained (mean and range, microgram/kg dry weight, N = 7-10): lung 173 (71-371), thyroid 141 (41-240), adrenal 132 (53-241), kidney 62 (19-171), heart 54 (10-110), liver 50 (11-102), brain 44 (20-65), spleen 37 (9-95), and pancreas 34 (7-71). In five specimens of gallbladder bile, nickel concentrations averaged 2.3 +/- 0.8 micrograms/l (range 1.5-3.3). These data furnish reference values for use in evaluating tissue nickel concentrations in persons with occupational exposures to nickel, provide the first demonstration that nickel concentrations in thyroid and adrenal glands are approximately equal to those in lung and are higher than in other organs, and suggest that biliary excretion may be a significant route for the elimination of nickel in humans.

Adult↗

PubMed1986

Sialic acid in human serum and cerebrospinal fluid. Comparison of methods and reference values.

Sialic acid was estimated simultaneously by three methods: chemical determination based on Warren's method (Meth. Enzymol. 6, 463-464 (1963) with slight modifications, enzymatic measurement with a commercially available test kit, and high performance liquid chromatography (HPLC) according to Silver et al. (J. Chromatogr. 224, 381-388 (1981). These methods showed closely correlated (r greater than 0.930) results and displayed similar precision data. Interference studies demonstrated sufficient specificity for the chemical assay, which was 5-6 times more sensitive than the enzymatic test and hence chosen for the establishment of reference values. From 249 sera from healthy people between 16 and 63 years the 0.025-0.975-reference intervals were calculated to be 1.57-2.63 mmol/l for 127 men, and 1.69-2.64 mmol/l for 122 women with no significant dependence on age and sex. From 43 cerebrospinal fluids from healthy adults the respective values were 17.3-50.4 mumol/l. These data correspond to those of the literature. Some chemical assays employing thiobarbituric acid were compared. They proved reliable in contrast to the reaction of serum with 4-dimethylaminobenzaldehyde.

Chemical Phenomena↗

PubMed1995

Ventilatory function measured with the Micro Spirometer: performance evaluation and reference values.

The performance of the Micro Spirometer was compared with that of the Vitalograph by assessing the extent of agreement between the instruments and the repeatability of measurements with each instrument. The Micro Spirometer tended to give lower readings of forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) than the Vitalograph, with wide limits of agreement. The values of these ventilatory functions measured with the Micro Spirometer were, therefore, not directly comparable with those obtained from the Vitalograph, and it is also not satisfactory to predict readings on the Micro Spirometer from those made on the Vitalograph. In the management of asthma patients, the PEFR would still be preferably measured with the mini Wright peak flow, given its low cost and established reliability compared with the standard Wright peak flow meter. The Micro Spiromoter has the practical advantages of portability, ease of operation and relative cheapness for the baseline and long-term assessment of FEV1 and FVC in ambulatory care, as well as in epidemiological studies. However, local users should not employ reference values provided by the manufacturer or those published in the literature, but those reported in this paper.

Adolescent↗

PubMed1998

Biological variations and genetic reference values for apolipoprotein E serum concentrations: results from the STANISLAS cohort study.

Serum apolipoprotein (apo) E concentrations were determined by immunoturbidimetry in 4284 subjects from 4 to 71 years of age and belonging to 1003 nuclear families recruited for the STANISLAS cohort study between January 1994 and August 1995. Values for apo E ranged from 16 to 169 mg/L, with a geometric mean +/- SD values of 46.6 +/- 13.8 mg/L in the overall sample. The interindividual variability varied from 24.6% to 32.0% among family members. Females exhibited higher apo E values than males until the age of 17-26 years. Conversely, after the age of 26 years, serum apo E concentrations were higher in men than in women. Biological factors affecting serum apo E concentrations were described in fathers, mothers, sons, and daughters and explained up to 32.0% of the apo E variability in daughters and 19.0% in fathers. The main biological factors affecting apo E concentrations were the following: apo E polymorphism, waist-to-hip ratio, oral contraceptive intake, puberty, body mass index, age, and gender. Given the importance of apo E polymorphism in the regulation of apo E concentrations, we recommend the use of genetic-based reference values for the clinical interpretation of serum apo E concentrations.

Adolescent↗

PubMed1985

Echocardiographic reference values in healthy cats sedated with ketamine hydrochloride.

An M-mode echocardiographic examination was performed in a consistent manner in 30 clinically healthy cats under light ketamine hydrochloride sedation. There was a significant linear relationship between increasing body size and increasing cardiac dimensions for several echocardiographic values. Positive correlation existed between body weight and body surface area with aortic root, left ventricular caudal wall thickness (LVCW), interventricular septal thickness (IVS), IVS/LVCW, and mean velocity of circumferential fiber shortening (Vcf); there was a negative correlation between body weight and body surface area with left ventricular ejection time (LVET). Body surface area also correlated positively with percentage of ventricular minor axis dimensional change (% delta D). Positive correlations were recorded between left ventricular end-diastolic dimension (LVEDD) and left ventricular endsystolic dimension (LVESD), LVESD and LVET, LVCW and IVS, LVET (calculated by LVCW motion) and LVET (calculated by aortic valve motion), % delta D and Vcf, heart rate and Vcf, and Vcf (calculated using aortic valve motion to compute LVET) and Vcf (using LVCW motion to compute LVET). There were negative correlations between LVEDD and % delta D, LVEDD and Vcf, LVESD and Vcf, LVET and Vcf, LVET and heart rate, LVET and % delta D. Significant differences were recorded between means of echocardiographic reference values generated in this and other studies, except for LVESD.

Animals↗

PubMed2001

Forced spirometry reference values for Norwegian adults: the Bronchial Obstruction in Nord-Trøndelag Study.

The purpose of this study was to develop new prediction equations for flow/volume spirometry parameters in asymptomatic, never-smoking adults in Norway, and to assess any differences of these parameters when applying the new and most commonly used equation sets. Flow/volume spirometry was measured according to the American Thoracic Society criteria in 2,792 subjects aged > or = 20 yrs, randomly selected from participants in the Nord-Trøndelag Health Study. Ever-smokers and subjects with respiratory symptoms and/or diseases reported in this questionnaire were excluded. A total of 546 females and 362 males met the inclusion criteria and were included in the analyses. Most lung function variables were nonlinear by age and had to be transformed. After a plateau in younger adults, the variables declined by age. The reference values for forced expiratory volume in one second and forced vital capacity from the present study, were higher than those given by prediction equations from the European Community for Coal and Steel, but in closer agreement with later studies from Europe, Australia and the USA. Healthcare providers should be encouraged to reconsider their choice of prediction equations of spirometry in order to improve management of obstructive lung diseases.

Adult↗

PubMedDate not supplied

Spirometry reference values for women and men aged 65-85 living in southern Europe: the effect of health outcomes.

BACKGROUND: Spirometry is more and more frequently used for the diagnosis of respiratory diseases in the elderly people. Unfortunately, reliable predictive values for the spirometric variables in the elderly are lacking. OBJECTIVES: Data obtained from 429 subjects participating in the multicenter Italian study SARA on respiratory health in the elderly were analyzed in order to derive reference values for spirometry in the age range of 65-85 years. The second aim of this study was to assess the influence of variables describing many dimensions of the health status on the prediction of spirometric variables in that age range. METHODS: Subjects were recruited as consecutive outpatients referred during the study period to 24 geriatric or respiratory institutions distributed throughout Italy. Spirometries were performed using the same equipment by specifically trained and certified personnel supervised by a real-time quality control program. In addition to the standard anthropometric variables, covariates describing the affective, mental, and general health conditions were investigated through standardized questionnaires, to improve the modeling of spirometric outcomes. RESULTS: Reliable predictive values for forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were produced (coefficient of determination, for FVC: R2 = 0.64; for FEV1: R2 = 0.54). The effect of general health conditions on spirometric outcomes accounted for the most part of the between-gender difference in the ageing-dependent decrease in lung function. CONCLUSIONS: We suggest that a multidimensional approach to health problems should be used for a better interpretation of spirometric results in the elderly.

Aged↗