SEARCH · PubMed Health

Results for “Reference Values”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources

PubMed1998

[Quebec spirometry reference values].

Lung volumes forced expiratory flow rates and carbon monoxide diffusing capacity (apnea) were measured in 397 non-smoking, nonatopic, asymptomatic subjects (219 women, 178 men). The equipments and methods for measurements met the ATS criteria. The linear regression of the different variables according to age and height allowed the elaboration of a new set of predictive equations (Quebec). When comparing the different reference values used in North America and Europe, it is found that those of Miller and associates as well as those recommended by the CECA provide the best description of the Quebec situation. However, we would eventually prefer the reference values of Miller and associates over those of the CECA, because they better fit the current ATS criteria and also provide references for smokers. Lung volumes and forced expiratory flow rates of 97 non-smoking, nonatopic, asymptomatic manual workers were measured in the same conditions and submitted to the same comparisons. Quebec predictive values as well as those of Miller and associates isolated the same individuals in the so called abnormal zone. We therefore conclude that Quebec's standards should be preferred in the Province of Quebec pulmonary function laboratories.

Adult↗

PubMed2005

Bone density at the os calcis: reference values, reproducibility, and effects of fracture history and physical activity.

AIMS: To establish reference values for bone mineral density (BMD) measured at the os calcis (OC) in healthy UK Caucasian children. Secondary objectives were to assess the reproducibility of the measurement and the effects of fracture history and habitual physical activity. METHODS: A total of 403 children aged 5-18 were studied. Main outcome measures were: BMDoc measured by peripheral DXA, total BMD measured by whole body axial scanner, age, anthropometry, pubertal status, self-reported fracture history, and physical activity (PA) expressed as a three point score. RESULTS: Complete data were available on 171 girls and 123 boys free of a history of fracture. BMDoc was related positively to age, body size, and total BMD, and could be predicted using a proportional model based on height alone (R2: 65% girls, 77% boys). Mean BMDoc appears to plateau in girls at 15 years and attain a value that concurs with the mean peak value in adult women. The 95% limits of agreement in repeated measures were -0.029 to 0.029 g/cm2 (n = 53). Compared with sedentary children, those doing regular sports or PA for more than five hours a week had an increased BMDoc (by about 0.03 g/cm2 or about 7% of the overall mean). A history of fracture (n = 81) was associated with a reduced BMDoc in boys but not in girls, though our study may have been underpowered for a subgroup analysis. CONCLUSIONS: BMDoc can be measured easily and quickly in children older than 5 years and provides an objective measure of areal bone density for clinical and research studies using a reference range derived from its relation to height.

Absorptiometry, Photon↗

PubMed2001

Reference values of interrupter respiratory resistance in healthy preschool white children.

BACKGROUND: Interrupter respiratory resistance (Rint) is reported to be useful in evaluating lung function in poorly collaborating patients. However, no reference values are available from large samples of preschool children using the standard interrupter method. The aim of this study was to define reference Rint values in a population of healthy preschool children. METHODS: Rint was assessed without supporting the cheeks in children with no history of wheeze from six kindergartens. To evaluate the effects of upper airway compliance on Rint in healthy children, an additional group of preschool children with either no history of wheeze or no respiratory symptoms at the time of testing underwent Rint measurements in our lung function laboratory with and without supporting the cheeks. Short term (about 1 minute apart) and long term (mean 2.5 months apart) repeatability of Rint measurements (2 SDs of the mean paired difference between measurements) was also assessed in children referred for cough or wheeze. RESULTS: A total of 284 healthy white children (age range 3.0-6.4 years) were evaluated. Mean inspiratory and expiratory Rint (RintI and RintE) did not differ significantly in boys and girls. Age, height, and weight showed a significant inverse correlation with both RintI and RintE in the univariate analysis with linear regression. Multiple regression with age, height, and weight as the independent variables showed that all three variables were significantly and independently correlated with RintI, whereas only height was significantly and independently correlated with RintE. Supporting the cheeks had no significant effect on RintI (n=29, median 0.673 v 0.660 kPa/l.s, p=0.098) or RintE (n=39, median 0.702 v 0.713 kPa/l.s, p=0.126). Short term repeatability was 0.202 kPa/l.s for RintI (n=50) and 0.242 kPa/l.s for RintE (n=69). Long term repeatability was 0.208 kPa/l.s for RintE (n=26). CONCLUSIONS: We have reported reference Rint values in preschool white children and have demonstrated the usefulness of this technique in assessing lung function in this age group.

Airway Resistance↗

PubMed1984

Hematology and biochemistry reference values for Ontario swine.

The purpose of this study was to establish blood reference values for Ontario swine from various age groups. Weanling pigs, feeder pigs, gilts and sows on 11 randomly selected swine farms were sampled using the orbital sinus bleeding technique. Routine hematological and biochemical determinations were performed using whole blood and serum. For the variables examined in each age group the means, the standard deviations and the 95% upper and lower limits were calculated.

Age Factors↗

PubMed1993

Reassessment for reference values for total nucleated cell count and myeloid/erythroid ratio of human bone marrow aspirate.

Total uncleated cell count and Myeloid/Erythroid (M/E) ratio of bone marrow aspirate in Japanese was determined in 1962 and no reassessment has been done until now. Therefore, the reassessment work has been performed using our laboratory data. Criterias for healthy individuals were settled and data obtained were applied first for probability plot analysis chart and data which gave asymmetry for the distribution curve were expelled. Then the data sets were processed with Hoffman's 3 time cutting method. As a result, reference values of the count and the ratio were obtained in total and by gender and age. The former values were lower than those reported by previous papers, but the latter values were similar to those reported previously. On the other hand, our manual counting method was compared with the electronic counting method, and good correlation was observed between the both. From the results we concluded that our reference values were acceptable and useful for routine use.

Bone Marrow Cells↗

PubMed1993

Determination of chromium in blood and serum: evaluation of quality control procedures and estimation of reference values in Danish subjects.

This paper describes analytical methods to estimate environmental and occupational exposure levels of chromium in blood and serum by Zeeman atomic absorption spectrometry. Also reported is an internal quality control procedure involving a combination of an online quality control and subsequent statistical evaluation of the quality control results to evaluate the performance of the analytical methods. The solubilization of the blood by the proteinase Subtilisin A resulted in a recovery of chromium of 106 +/- 4.5%; the uncertainty was approximately 10% at a chromium level of 1 microgram l-1. The detection limit (LOD) for chromium in serum was 0.17 micrograms l-1 and 0.20 micrograms l-1 for chromium in blood. The LODs were sufficiently low for the determination of chromium in a large fraction of reference populations not occupationally exposed. The present study indicates that reference values for chromium in blood and serum are low but within the range in recent investigations, i.e. 0.04-0.35 micrograms l-1 in serum and 0.12-0.34 micrograms l-1 in human whole blood. The fraction of reference values below LOD was between 0.45 and 0.57 for chromium in serum and blood. Consequently, the reference populations were described by distribution free one-sided tolerance intervals and the precision of the estimation of the tolerance intervals was expressed as coverage intervals. The 95% one-sided tolerance limit calculated for chromium in serum was 0.60 micrograms l-1 with the coverage interval (95 +/- 4.8) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval covers at least 90.2% of the distribution. In addition, the probability was 0.025 that the tolerance interval covers more than 99.8% of the population. It was only possible to calculate the 90% tolerance interval for chromium in blood with the coverage interval at 0.90 probability. The one-sided tolerance interval for chromium in blood was 0.37 micrograms l-1 with the coverage interval (90 +/- 9.9) percent at a probability of 0.90.

Chromium↗

PubMedDate not supplied

[Spirometric reference values in black females].

The aim of this paper is to give spirometric reference values for black females. Having eliminated those with abnormal hemoglobin, we studied 298 females aged between 10 to 70 years: 15 from bordering countries of the Ivory Coast and the others being Ivorian. That is, they are all from West Africa. It is shown that FVC and FEV1 are reduced in the black population when compared with European whites. Volume and flow values are also lower than those in Ivorian men. Correlations and linear regression equations were calculated between FVC, FEV1 and age, height, and weight. FVC and FEV1 (l BTPS) were found as a function of height H (m) and age A (years) as follows: from 10 to 25 years, FVC = 0.465 H3 + 0.01735 A + 0.58; FEV1 = 0.451 H3 + 0.0035 A + 0.61; from 25 to 70 years, FVC = 0.450 H3 - 0.02002 A + 1.54; FEV1 = 0.309 H3 - 0.02050 A + 1.44.

Adolescent↗

PubMed2006

Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): standardized protocol and reference values.

The nationwide multicenter trials of the German Research Network on Neuropathic Pain (DFNS) aim to characterize the somatosensory phenotype of patients with neuropathic pain. For this purpose, we have implemented a standardized quantitative sensory testing (QST) protocol giving a complete profile for one region within 30 min. To judge plus or minus signs in patients we have now established age- and gender-matched absolute and relative QST reference values from 180 healthy subjects, assessed bilaterally over face, hand and foot. We determined thermal detection and pain thresholds including a test for paradoxical heat sensations, mechanical detection thresholds to von Frey filaments and a 64 Hz tuning fork, mechanical pain thresholds to pinprick stimuli and blunt pressure, stimulus/response-functions for pinprick and dynamic mechanical allodynia, and pain summation (wind-up ratio). QST parameters were region specific and age dependent. Pain thresholds were significantly lower in women than men. Detection thresholds were generally independent of gender. Reference data were normalized to the specific group means and variances (region, age, gender) by calculating z-scores. Due to confidence limits close to the respective limits of the possible data range, heat hypoalgesia, cold hypoalgesia, and mechanical hyperesthesia can hardly be diagnosed. Nevertheless, these parameters can be used for group comparisons. Sensitivity is enhanced by side-to-side comparisons by a factor ranging from 1.1 to 2.5. Relative comparisons across body regions do not offer advantages over absolute reference values. Application of this standardized QST protocol in patients and human surrogate models will allow to infer underlying mechanisms from somatosensory phenotypes.

Adolescent↗

PubMed1995

Normal behaviour of circulatory parameters during exercise. Reference values for heart rate and systemic blood pressure. The ECCIS Project data. Epidemiologia e Clinica della Cardiopatia Ischemica Silente.

The study of simultaneous variations in heart rate (HR) and systemic blood pressure is of great interest in ergometric practice complementing the analysis of the ST segment by ECG. This paper examines data proceeding from 500 consecutive, normal, exercise stress tests with the aim of offering reference values on the step-by-step behaviour of HR, systolic and diastolic blood pressure (SBP, DBP) during exercise in a normal population. The sample comes from a large epidemiological study (ECCIS Project) conducted on 4842 healthy, working men, aged 40-59, which proposes to identify, by a 3 stage procedure, subjects with totally asymptomatic coronary artery disease (type I silent ischemia). A further aim of our paper is to examine the influence of some physiological variables (age, height, weight, body mass index, resting HR, SBP and DBP) on the response to effort of HR, SBP and DBP; reciprocal HR/SBP adjustment during exercise; maximal attained workload and recovery time. Due to a preliminary observation that the rate of step-by-step increase in HR and SBP is inversely related to total duration, the population was split into 4 groups according to exercise tolerance (defined by maximal attained workload) to elaborate reference values. Furthermore our data demonstrate that: 1) SBP increases more rapidly with respect to HR for older and heavier subjects; 2) Exercise tolerance is inversely related to age, baseline HR and SBP, and directly related to weight and height; 3) return to baseline conditions, during recovery, is quicker for subjects with better exercise tolerance and lower baseline HR, SBP and weight.

Adult↗

PubMed2001

Reference values for the physical work capacity on a bicycle ergometer for women between 20 and 80 years of age.

A sample of women (n=87) uniformly distributed in age (20-80 years) was randomly selected from the municipal population register and conventional clinical exercise tests were performed on a bicycle. The load started at 30 W and increased (5 W/30 s) until exhaustion. Care was taken to perform a maximum exercise test. The women were required to be cardiovascularly healthy and not on regular medication to be included in the study. The maximum work load was found to be dependent on age and height. The following equation described the maximum load. Max load (W)=(137.7 * Height (m) - 23.1)/(1 + exp (0.064 * (Age (years) - 75.9))). The upper and lower limits of the reference interval were 120 and 80% of the predicted load, respectively. The upper and lower limits for maximum heart rate were 110 and 90% of the maximum heart rate given by 190.2/(1 + exp (0.0453 * (Age - 107.5))). The reference value for maximum systolic blood pressure was taken as the interval between the two lines 153.3 + 0.281 * Age and 172.0 + 1.13 * Age. The reference values presented for work capacity are higher than those normally used in Sweden.

Adult↗

PubMed2000

Assay of D-lactate in urine of infants and children with reference values taking into account data below detection limit.

Accumulation of D-lactic acid produced by intestinal bacteria such as streptococci and lactobacilli has been extensively studied in ruminants [1-4]. In humans an increased production of D-lactate by intestinal bacteria under pathological conditions such as the short bowel syndrome can cause metabolic acidosis [5-8]. Since the lactate assays routinely used only measure L-lactate we developed a sensitive method of D-lactate quantification and established reference values in spot urines of infants and children (0 to 4 years of age). The enzymatic method with fluorimetric quantification of NADH is linear up to 2 mmol/l. It has a detection limit of 3.4 micromol/l. Among structurally related organic acids an interference was found only for L-lactate and DL-2-hydroxybutyrate at concentrations which are way beyond their physiological excretion. One hundred and sixty five spot urines of healthy Swiss (S), Austrian (A), German (G) and Chilean (CHI) infants aged from 0 to 4 years were analyzed. The distribution of the data is close to a lognormal one. Values below the detection limit were simulated and age groups were formed. In all populations D-lactate excretion was found highest during the first year of life; it declines with age during infancy and remains stable from 2.5 to 4 years of age. We show that D-lactate is excreted physiologically by healthy infants and children below 4 years of age and present reference values for D-lactate excretion which show some differences between the populations tested.

Aging↗

PubMed2001

Total body water reference values and prediction equations for adults.

BACKGROUND: The clinical interpretation of total body water (TBW) necessitates the availability of timely comparative reference data. The prediction of TBW volume in renal disease is critical in order to prescribe and monitor the dose of dialysis in the determination of Kt/V. In clinical practice, urea distribution (V) is commonly predicted from anthropometric equations that are several decades old and for white patients only. This article presents new reference values and prediction equations for TBW from anthropometry for white and black adults. METHODS: The study sample included four data sets, two from Ohio and one each from New Mexico and New York, for a total of 604 white men, 128 black men, 772 white women, and 191 black women who were 18 to 90 years of age. The TBW concentration was measured by the deuterium or tritium oxide dilution method, and body composition was measured with a Lunar DXA machine. An all-possible-subsets of regression was used to predict TBW. The accuracy of the selected equations was confirmed by cross-validation. RESULTS: Blacks had larger TBW means than whites at all age groups. The 75th TBW percentile for whites approximated the TBW median for blacks at most ages. The white men and black men and women had the largest TBW means ever reported for healthy individuals. The race- and sex-specific TBW prediction equations included age, weight, and stature, with body mass index (BMI) substituted for weight in the white men. The root mean square errors (RMSEs) and standard errors for the individual (SEIs) ranged from approximately 3.8 to 5.0 L for the men and from 3.3 to 3.6 L for the women. In both men and women, high values of TBW were associated with high levels of total body fat (TBF) and fat-free mass (FFM). CONCLUSION: : TBW in these healthy adults is relatively stable through a large portion of adulthood. There are significant race and sex differences in TBW. These accurate and precise equations for TBW provide a useful tool for the clinical prediction of TBW in renal disease for white and black adults. These are the first TBW prediction equations that are specific for blacks.

Adult↗

PubMedDate not supplied

Echocardiographic measurements in the Irish wolfhound: reference values for the breed.

Out of 400 Irish wolfhounds cardiologically examined, echocardiographic measurements of 262 normal dogs were analyzed to obtain reference values for the breed. Based on regression analysis, several echocardiographic parameters showed significant linear correlation with body weight and with age, but coefficients of determination were low. Therefore, due to a high individual variability of echocardiographic measurements in adult Irish wolfhounds, the predictive value of body weight for echocardiographic measurements was clinically not relevant. Sex had no influence on echocardiographic values. For the estimation of myocardial function, end-systolic volume index (ESVI) (mean, 29.0 ml/m2 +/- standard deviation [SD], 5.9 ml/m2) was determined for the group of 262 normal dogs.

Animals↗

PubMed2004

New reference values for thyroid volume by ultrasound in iodine-sufficient schoolchildren: a World Health Organization/Nutrition for Health and Development Iodine Deficiency Study Group Report.

BACKGROUND: Goiter prevalence in school-age children is an indicator of the severity of iodine deficiency disorders (IDDs) in a population. In areas of mild-to-moderate IDDs, measurement of thyroid volume (Tvol) by ultrasound is preferable to palpation for grading goiter, but interpretation requires reference criteria from iodine-sufficient children. OBJECTIVE: The study aim was to establish international reference values for Tvol by ultrasound in 6-12-y-old children that could be used to define goiter in the context of IDD monitoring. DESIGN: Tvol was measured by ultrasound in 6-12-y-old children living in areas of long-term iodine sufficiency in North and South America, central Europe, the eastern Mediterranean, Africa, and the western Pacific. Measurements were made by 2 experienced examiners using validated techniques. Data were log transformed, used to calculate percentiles on the basis of the Gaussian distribution, and then transformed back to the linear scale. Age- and body surface area (BSA)-specific 97th percentiles for Tvol were calculated for boys and girls. RESULTS: The sample included 3529 children evenly divided between boys and girls at each year ( +/- SD age: 9.3 +/- 1.9 y). The range of median urinary iodine concentrations for the 6 study sites was 118-288 micro g/L. There were significant differences in age- and BSA-adjusted mean Tvols between sites, which suggests that population-specific references in countries with long-standing iodine sufficiency may be more accurate than is a single international reference. However, overall differences in age- and BSA-adjusted Tvols between sites were modest relative to the population and measurement variability, which supports the use of a single, site-independent set of references. CONCLUSION: These new international reference values for Tvol by ultrasound can be used for goiter screening in the context of IDD monitoring.

Child↗

PubMed2001

Reference values of maximum isometric muscle force obtained in 270 children aged 4-16 years by hand-held dynamometry.

Since muscle force and functional ability are not related linearly; maximum force can be reduced while functional ability is still maintained. For diagnostic and therapeutic reasons loss of muscle force should be detected as early and accurately as possible. Because of growth factors, maximum muscle force in children varies with age, which makes detection of force loss difficult. The purpose of this study was to establish reference values for muscle force in children aged 4-16 years, obtained by hand-held dynamometry in 11 muscle groups. In boys muscle force was predicted best by weight whereas in girls weight and age were best predictors. At age 14 boys become significantly stronger for nearly all tested muscle groups. These age-related reference values can be used to quantify muscle weakness in individual muscle groups in children aged 4-16 years and to evaluate the effects of therapy.

Adolescent↗

PubMed2002

[Reference values in the cerebrospinal fluid of calves between four and eight weeks of age].

Reference values for the following parameters were established in the cerebrospinal fluid of 27 calves between four and eight weeks of age: specific weight, protein concentration, erythrocyte count, total leucocyte count with cell differentiation, creatin kinase activity, glucose and sodium. If possible, the findings were compared with those of other authors in calves and adult bovines. With 24.3 cells per microliter the 90% quantile of the total leucocyte count was seated significantly above comparable values for adult bovines. Hence, in individual cases markedly higher leucocyte counts can be expected in the cerebrospinal fluid of calves. In agreement with other authors, the protein concentration in calves was lower than in adult bovines. The reference range for creatin kinase activity was increased whereas the one for sodium was only slightly increased compared to earlier investigations in calves and in adult bovines.

Animals↗

PubMed2002

Cardiovascular autonomic nervous system tests: reference values in young people (15-19 years) and influence of age and gender.

OBJECTIVE: The aim of this study was to determine values of the deep breathing test (DB), orthostatic test (OT) and Valsalva manoeuvre (VM) parameters in young people and influence of age and gender. METHODS: A total of 206 healthy subjects (100 girls, 106 boys) at the age of 15-19 years, BMI 21.3+/-2.3 (mean +/- SD) were examined by system Varia Pulse TF3. RESULTS: Reference values of DB, OT, VM parameters are presented as arithmetic mean +/- SD and percentiles (P90, P75, P50, P25, P10). In the whole group HRrest was lower in 19-year-old group, in OT this difference was significant already in 18-year-old group compared with 15-year-old group. DB: I/E was significantly increased in 19-year-old group compared with 15-year-old group. HRrest was higher in girls compared with boys in the whole group. DB: I/E was significantly lower in girls compared with boys. OT: 30:15 and HRmax/HRrest were significantly decreased in girls compared with boys. CONCLUSION: Reference values of DB, OT, VM parameters were determined in young people at the age of 15-19 years. The most sensitive test for ascertainment of developmental changes was test of deep breathing. I/E was increased in the 19-year-old group compared with 15-year-old group indicating an increase of vagal activity. Girls had decreased some parameters of deep breathing and orthostatic test compared with boys in the same group (15-19 years).

Adolescent↗

PubMed1996

[Assessment of 2 portable peak expiratory flow meters and reference values for students 6 to 16 years of age].

OBJECTIVE: This study examines the technical characteristics of two different peak expiratory flow meters, of high range, and the reference values of peak expiratory flow (PEF) for schoolchildren. PATIENTS AND METHODS: The gauge accuracy and precision were previously determined in 20 units of each model (PF-Control and Mini-Wright), with a syringe servocontrolled by simulating 4 predetermined PEF fluxes (125, 262, 424 and 587 L/min). Relatives were asked about passive smoking and the childhood background concerning asthma, recurrent bronchitis or recent respiratory infection. The PEF of 1,142 schoolchildren, 669 boys and 473 girls between 6 and 16 years of age and coming from 6 different locations of different demographic and social characteristic of Catalonia, Spain, were measured. RESULTS: Readings of both gauges differed in accuracy, although they presented a good intradevice precision. The PF-control is within the reliance intervals for fluxes of 425 and 587 L/min, with a suprareading of 15.3% for the 262 L/min and infrareading of 19.2% for the 125 L/min controls. Flux with the Mini-Wright shows systematic over-reading of between 17.9% and 30.2%, with an accurate reading only in the 587 L/min control flux. No significant correlation was found between the PEF and family passive smoking (56.3%), pupils with asthma background (7.1%), recurrent bronchitis (11%) or recent respiratory infection (7.7%). CONCLUSIONS: The accuracy difference forces the use of diverse percentile tables for each of the PEF gauge patterns; hence, we present the reference tables for each gauge, in means of 10, 50 and 90 percentiles, which can be used as reference values for our school population according to their age, size and sex.

Adolescent↗