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At least 127 records · Page 7Linked to original sources

PubMed2001

Determination of reference values for glucose tolerance, insulin tolerance, and insulin sensitivity tests in clinically normal cats.

OBJECTIVE: To determine reference values and test variability for glucose tolerance tests (GTT), insulin tolerance tests (ITT), and insulin sensitivity tests (IST) in cats. ANIMALS: 32 clinically normal cats. PROCEDURE: GTT, ITT, and IST were performed on consecutive days. Tolerance intervals (ie, reference values) were calculated as means +/- 2.397 SD for plasma glucose and insulin concentrations, half-life of glucose (T1/2 glucose), rate constants for glucose disappearance (Kglucose and Kitt), and insulin sensitivity index (Si). Tests were repeated after 6 weeks in 8 cats to determine test variability. RESULTS: Reference values for T1/2glucose, Kglucose, and fasting plasma glucose and insulin concentrations during GTT were 45 to 74 minutes, 0.93 to 1.54 %/min, 37 to 104 mg/dl, and 2.8 to 20.6 microU/ml, respectively. Mean values did not differ between the 2 tests. Coefficients of variation for T1/2glucose, Kglucose, and fasting plasma glucose and insulin concentrations were 20, 20, 11, and 23%, respectively. Reference values for Kitt were 1.14 to 7.3%/min, and for SI were 0.57 to 10.99 x 10(4) min/microU/ml. Mean values did not differ between the 2 tests performed 6 weeks apart. Coefficients of variation for Kitt and SI were 60 and 47%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: GTT, ITT, and IST can be performed in cats, using standard protocols. Knowledge of reference values and test variability will enable researchers to better interpret test results for assessment of glucose tolerance, pancreatic beta-cell function, and insulin sensitivity in cats.

Animals↗

PubMed1997

Comfortable and maximum walking speed of adults aged 20-79 years: reference values and determinants.

OBJECTIVES: to establish reference values for both comfortable and maximum gait speed and to describe the reliability of the gait speed measures and the correlation of selected variables with them. DESIGN: descriptive and cross-sectional. METHODS: subjects were 230 healthy volunteers. Gait was timed over a 7.62 m expanse of floor. Actual and height normalized speed were determined. Lower extremity muscle strength was measured with a hand-held dynamometer. RESULTS: mean comfortable gait speed ranged from 127.2 cm/s for women in their seventies to 146.2 cm/s for men in their forties. Mean maximum gait speed ranged from 174.9 cm/s for women in their seventies to 253.3 cm/s for men in their twenties. Both gait speed measures were reliable (coefficients > or = 0.903) and correlated significantly with age (r > or = -0.210), height (r > or = 0.220) and the strengths of four measured lower extremity muscle actions (r = 0.190-0.500). The muscle action strengths most strongly correlated with gait speed were nondominant hip abduction (comfortable speed) and knee extension (maximum speed). CONCLUSIONS: these normative values should give clinicians a reference against which patient performance can be compared in a variety of settings. Gait speed can be expected to be reduced in individuals of greater age and of lesser height and lower extremity muscle strength.

Adult↗

PubMed1991

Reference values for some fundamental haemostatic factors in the dog.

The study is a methodological survey to define the reference values for some basic haemostatic parameters in healthy dogs. Reference values for PT, APTT and factors VIII:C and IX:C were studied in 34 dogs. The reference values were (minimum-maximum) 6.5-9.5 and 17.5-26.3 seconds for PT and APTT, 58-260% and 67-163% for VIII:C and IX:C respectively and 185.8-354.4 x 10/1 for platelets. These reference values were applied to 130 other dogs which were presented to the clinic for various treatments or health checks. The results show how haemostatic analysis can be used to resolve delicate interpretation of laboratory results.

Animals↗

PubMedDate not supplied

[Patient data for evaluating reference values].

OBJECTIVE: To explore the use of data in patients as a way to evaluate the values of reference in clinical assays. Serum calcium (Ca) and phosphorus (P) were selected for this purpose. MATERIAL: A total of 836 consecutive admissions in a 10 week period were revised. Seventy percent (580 cases) had data of Ca and P in the first week following admission. A total of 424 were excluded by anyone of the following criteria: a) serum urea greater than 50 mg/dL, b) serum creatinine greater than 1.5 mg/dL; c) serum albumin less than 4 g/dL; d) lack of data of either urea, creatinine or albumin. These cutoff values were selected on the basis of a significant difference (t test) in the mean of Ca and/or P in patients grouped according to levels of the available data. The remainder of 156 cases is the selected population of study, and the 580 with Ca and P is the total population. METHODS: Ca and P were assayed in an analyzer (Coulter Chemistry) using the DAM and the Jaffé methods respectively. The precision during the period of study was adequate (CVs of 2.6% for Ca and 2.9% for P). RESULTS: Table 1 compares the mean, SD and CV of Ca and P in the selected versus the total population. There are significant reductions (F test) in the variability of Ca and P in the selected population (from a CV 9 to 5% in Ca and from 35 to 13% in P). Table 2 compares the age and sex distributions of the selected versus the total population. There are no significant differences (chi square test) although there is a lower proportion of people above 80 years of age in the selected population. The reference intervals of Ca and P in the selected population were obtained with the mean +/- 2 SD as both showed Gaussian distributions. These limits are compared in table 3 versus the values of the institution and of the manufacturer of the analyzer used. The P limits of this study fall intermediate to the other two, but in Ca they are the lowest of the three. Shortly after the completion of this study, the institutional values of Ca were changed to 8.5-10.5 mg/dL on the basis of the one year results in a WHO quality assessment scheme. The modification made the Ca limits of this study also intermediate to the other two series. The small differences in the limits have clinical and economic repercussions. Table 4 shows there is a 20% reduction in the number of abnormal tests (206 vs 259) and in the number of abnormal individuals (165 vs 203) using the limits of this study versus the institutional limits before modification. CONCLUSIONS: The data of Ca and P in a selected but representative population of patients proved to be a reliable way of evaluating its reference intervals. The reference intervals of this study were intermediate to those of the manufacturers of the analyzer and the laboratory (after modification). This finding suggests the strategy may be as good as more conventional approaches to establish reference values.

Adolescent↗

PubMed1997

Population-specific reference values for bone age.

Contemporary reference values for assessing skeletal maturity have been obtained for the Japanese population. These were used to compare skeletal maturation with populations from the UK. Belgium, North India and South China. Japanese children were found to attain skeletal maturity, based on measurements of the radius, ulna and short bones of the left hand and wrist, 1 or 2 years earlier than present-day European and Chinese children. A relative lack of data for the North Indian population made comparison impossible.

Age Determination by Skeleton↗

PubMed1996

Lung function in healthy never smoking adults: reference values and lower limits of normal of a Swiss population.

BACKGROUND: Reference values and definitions of "normal" are prerequisites for population screening and classification of lung diseases. The aim of this study was to calculate reference values for never smoking Caucasian adults. METHODS: In the SAPALDIA cross sectional study respiratory health was assessed in a random sample of 9651 subjects, aged 18-60 years, from eight areas of Switzerland. Lung function was measured according to ATS criteria including quality control. In 3157 healthy never smoking adults without respiratory symptoms the mean values and fifth percentiles of lung function variables were calculated. For each sex, logarithms of lung function were regressed against age, age squared, and the logarithm of height. Residuals were used to estimate fifth percentiles across the age range using a technique not requiring normality or homoscedasticity of residuals. RESULTS: Most lung function variables were non-linear with age and showed an increase in early adulthood and an accelerated decline thereafter. The reference values for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were higher than those of the European Community for Coal and Steel and those from North America. The prediction equations for lower fifth percentile values defined a stable proportion of subjects outside this limit whereas alternative methods for estimating the fifth percentile showed a loss of sensitivity with age. CONCLUSIONS: The reference equations for mean values of spirometric indices and their lower fifth percentiles gave an improved and unbiased lower limit of normal. The higher mean values may in part be due to the strictly selected population, quality control procedures, cohort effects, and altitude, and are not explained by the statistical model used.

Adolescent↗

PubMed1991

[Reference values of dipolar electrocardiotopography of the QRS complex].

Reference values of dipolar electrocardiotopogram of ventricular depolarization are presented. The data for establishing reference values in the McFee-Parungao lead system were obtained by manual processing of 145 records of healthy subjects (64 women, 81 men) in the age range of 11-72 years, and for the Frank lead system by automatic processing of 123 records of healthy subjects (54 women, 69 men) aged from 9 to 72 years. The obtained values of the X, Y, Z coordinates of the end points of QRS instantaneous vectors recorded at 10 ms intervals were processed by means of a biomathematical model in the form of activation areas on the spherical image surface. Electrocardiotopograms were represented in the form of discrete spherical image surface in the shape of a rectangle (11 lines, 24 columns). For each point of this matrix the value of relative frequency (probability) of its occurrence in activated state in the healthy population is given.

Adult↗

PubMed1998

Reference values for 24-hour ambulatory blood pressure monitoring based on a prognostic criterion: the Ohasama Study.

Although reference values for ambulatory blood pressure (ABP) monitoring have been investigated in several population studies, these values were derived from cross-sectional observations and were based merely on the statistical distribution of blood pressure values. Therefore, we conducted a prospective cohort study to identify reference values for 24-hour ABP in relation to prognosis. We obtained measurements of 24-hour ABP for 1542 subjects (565 men) aged 40 years and over in a general population of a rural Japanese community and then followed-up their survival status. There were 117 deaths during the follow-up period (mean, 6.2 years). The association between baseline 24-hour ABP values and mortality, examined by the Cox proportional hazards regression model adjusted for possible confounding factors, showed a better fit with a second-degree equation than with a first-degree equation. On the basis of the results of this analysis, we identified the following reference values as the optimal blood pressure ranges that predict the best prognosis: 120 to 133 mm Hg for systolic blood pressure and 65 to 78 mm Hg for diastolic blood pressure. 24-Hour ABP values >134/79 mm Hg and <119/64 mm Hg were related to increased risks for cardiovascular and noncardiovascular mortality, respectively. This is the first report to propose reference values for 24-hour ABP based on a prognostic criterion.

Adult↗

PubMed1989

Health-based reference values of the Mini-Finland Health Survey: 1. Serum gamma-glutamyltransferase, aspartate aminotransferase and alkaline phosphatase.

The reference values for gamma-glutamyltransferase (GT), aspartate aminotransferase (ASAT) and alkaline phosphatase (AFOS) activities in serum have been produced on the basis of measurements done in the Mini-Finland Health Survey. A representative sample of all Finns aged 30 years or over comprised 8000 persons, of whom 99.2% participated in the actual health survey. Every effort was made to obtain reference values for the healthy ambulatory population. Three separate health-derived selection criteria were used to obtain such reference values for the above-mentioned enzymes: those based on the available literature, with minor modifications, the recommendations published by the Committee on Reference Values of the Scandinavian Society for Clinical Chemistry and Clinical Physiology, criteria that were obtained after subgroup comparisons of the obtained data, where all the factors affecting the enzyme levels were identified. The recommendations of the Expert Panel on Theory of Reference Values (1987) were strictly adhered to in the statistical analyses. The distribution of the serum activity of GT was very skewed. The overall intervals for men and women were 5.1-1460 and 4.7-748 U/l, respectively. The frequency distributions could be transformed to the normal ones logarithmically. The 95% inner reference intervals for GT in the three groups were 7-76, 7-65, and 8-57 U/l for men and 6-35, 6-30 and 6-32 U/l for women, respectively. For ASAT the full intervals of the enzyme levels in serum were 2.6-770 U/l for men and 8.3-172 U/l for women. After logarithmic transformation the respective reference intervals in the three selection groups were 14-42, 14-40 and 13-39 U/l for men and 13-33, 12-31 and 13-33 U/l for women. The full intervals of AFOS were 47.5-2755 and 5.4-816 U/l for men and women, respectively; after the logarithmic transformation the reference intervals of the three selection groups were 98-267, 97-254 and 97-264 U/l for men and 77-265, 75-231 and 75-250 U/l for women, respectively.

Adult↗

PubMed1995

[Reference values of laboratory tests: a useful and important epidemiologic contribution of the Centers for health tests].

Since 1969 the Centre for Preventive Medicine in Nancy has been carrying out health examinations of the eastern region of France (Lorraine, Champagne-Ardenne). The clinical chemists at the Centre of Preventive Medicine have made a great contribution to the concept and the description of biochemical reference values for which the transferability to other health centres must be verified. Knowledge of reference values and biological variations facilitates the interpretation of weak modifications of biological constituents which are observed in preventive medicine. Reference values can be used to compare two populations (comparing reference values between to two) or to compare an individual observed value to the reference values obtained in the various population groups. In the long term, these reference values could become a useful education tool for patients coming for health examination. It should be possible for each subject to follow, throughout his life, the evolution of his biological constituents and to detect any deviation towards a pathology.

Diagnostic Tests, Routine↗

PubMed1998

Establishment of reference values for endocrine tests. I: Cushing's syndrome.

BACKGROUND: For diagnostic tests used in the evaluation of patients with Cushing's syndrome, well defined reference values were lacking in our laboratory. In the present study, we established reference values based upon test results of 50 subjects recruited from the general population. METHODS: We studied 50 subjects not suspected of having Cushing's syndrome, equally distributed according to sex and age between 20 and 69 years. In addition to 24 h urinary excretion of free cortisol for two days, a low-dose (1 mg) overnight dexamethasone suppression test, a corticotropin releasing hormone stimulation test (CRH test) and a high-dose (7 mg) intravenous dexamethasone suppression test were performed. Reference values are given as the observed range. RESULTS: There was considerable intra-subject variation in 24 h urinary cortisol excretion which could not be merely attributed to incompleteness of the urine collection. The following reference values were established: 24 h urinary free cortisol excretion: 15-145 nmol/24 h; overnight dexamethasone suppression test: cortisol on day 2 < 50-230 nmol/l; CRH test: cortisol increase 15-289%, ACTH increase 36-12.100%; high-dose, intravenous dexamethasone suppression test: cortisol after 7 h < 50-97 nmol/l; cortisol after 24 h < 50-50 nmol/l. There were no significant effects of age on any of the parameters studied. Apart from higher basal ACTH plasma concentrations in men, no sex differences were observed. CONCLUSION: We established reference values for tests that can be useful in the evaluation of patients with possible Cushing's syndrome.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Using reference values in pulmonary ventilation studies.

The aim of this study was to examine the discriminating power of six widely used, or recently introduced, reference values in the interpretation of pulmonary ventilation (FVC and FEV1) in occupational health surveys. These six reference values were applied to a sample of 400 Italian males; 200 of the sample were foundry workers and the other 200 were workers who were not occupationally exposed to dusts; 50% of each group were smokers. The relationship between the reference values and their capacity to discriminate between the workers occupationally exposed to dusts and the workers who smoked in each group was evaluated. The results showed very significant differences among the various reference values. Generally speaking these differences may be determined by the different selection criteria of the subjects under study, or may be a result of the different characteristics of the population included in the various studies. Our conclusions show the need for a critical approach to the use of reference values, particularly during screening tests.

Adult↗

PubMed1999

[Reference values for IGF-I, IGFBP-1, IGFBP-3 and osteocalcin in healthy children in Zaragoza].

OBJECTIVE: Our aim was to estimate reference values for basal serum concentrations of insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-1, IGFBP-3 and osteocalcin in healthy children of Zaragoza. PATIENTS AND METHODS: The reference population consisted of healthy children between 0 and 14 years of age with normal weight and height and living in the metropolitan area of Zaragoza (Spain). It was a transversal study. Immunoradiometric assays were used to determine basal serum IGF-I, IGFBP-1, IGFBP-3 and osteocalcin concentrations. Reference values and ranges were estimated according to the recommendations of the International Federation of Clinical Chemistry. RESULTS: Reference values have been classified according to age, sex and pubertal stage. IGF-I, IGFBP-1, IGFBP-3 and osteocalcin concentrations differ during the pubertal period according to age. There are differences in IGF-I, IGFBP-3 and osteocalcin levels between prepuberty and puberty and differences in IGF-I and osteocalcin levels among the pubertal stages. Sex did not influence IGF-I or IGFBP-1 concentrations and there were punctual differences in IGFBP-3 and osteocalcin levels between girls and boys. CONCLUSIONS: Sincere there are differences in IGF-I, IGFBP-1, IGFBP-3 and osteocalcin reference values according to age, sex, pubertal stage and immunoassays, it is necessary to establish the reference values for each population and laboratory in accordance with these parameters.

Adolescent↗

PubMedDate not supplied

Hematologic and clinical chemistry reference values in red lories (Eos spp.).

We established reference ranges for three hematologic and 15 clinical chemistry parameters of 40 clinically healthy birds of the genus Eos. The following species were included to the study: Eos histrio (n = 19), Eos squamata (n = 8), Eos bomea (n = 5), Eos reticulata (n = 4), Eos cyanogenia (n = 4). Detailed information concerning methodology, which is often missing in papers dealing with reference values, is included. As far as possible, data are compared with literature, and some thoughts on obvious deviations are given. The problem of establishing reference values in rare species is reviewed.

Animals↗

PubMed1999

Comparison of lung-function reference values.

OBJECTIVE: Lung-function reference values play an important role in medical surveillance examinations of occupational and environmental respiratory diseases, in stipulation of preventive measures, in initiation of therapeutic measures, and in granting of benefits to which individuals with lung injuries or occupational lung diseases are entitled (e.g., bronchial asthma, pneumoconiosis, or farmer's lung disease). Prediction equations most widely used are based on studies performed more than 20 years ago and may not represent the findings obtained in today's population. METHODS: We recorded case histories and lung function values of 139 healthy subjects (spirometric and plethysmographic data, T(LCO)) and computed the differences of measured values minus predicted ones as recommended by different authors. RESULTS: The means of these differences can be seen as shifts in our group versus the theoretical (predicted) values of various authors. These shifts, the standardized mean values of residuals, and their probability as determined under the assumptions of the respective regression model and the number of subjects below the threshold limits are given. FVC, FEV1, and FEV1%FVC show mostly good agreement with the recommendations by Crapo et al., Roca et al., Glindmeyer et al., Brändli et al., and Berger et al. Our IVC and FVC values do not differ significantly from each other. Normative flow-volume curve parameters of various authors deviate widely, however, and are not compatible with the values of our control group. Plethysmographically measured volumes (FRC, TLC, and RV) are only insufficiently reflected by Quanjer's reference equations. Measured T(LCO) and K(CO) show good agreement with the predictions of Cotes et al. [11] for females but display less concurrence with the predictions for males. CONCLUSIONS: Our results indicate that the ERS values of FVC, FEV1, and FEV1%FVC mainly applied in Europe should be verified. The much better-evaluated formulas of Brändli et al. are recommended. Furthermore, the age range between 60 and 70 years should be extrapolated from these formulas until better epidemiological data on lung function are available.

Adolescent↗

PubMedDate not supplied

Reference values for arm muscle area, arm fat area, subscapular skinfold thickness, and sum of skinfold thicknesses for American adults.

Reference values for the mid-upper arm muscle area, mid-upper arm fat area, subscapular skinfold thickness, and sum of triceps and subscapular skinfold thicknesses of American adults were developed from data collected by the National Center for Health Statistics during the first National Health and Nutrition Examination Survey, 1971 to 1974. The reference values were compared to other reference values derived from a similarly conducted cross-sectional survey of the American population, the Health Examination Survey of 1960 to 1962. These comparisons revealed that arm muscle area and subscapular skinfold thickness of men and arm muscle area of women continuously increase with aging from 18 to 74 yr; arm fat area and sum of skinfold thicknesses of men increase with aging from 18 to 34 yr but stabilize or decrease with further aging; and arm fat area, subscapular skinfold thickness, and sum of skinfold thicknesses of women increase with aging from 18 to 64 yr but decrease thereafter. As these parameters frequently change more than 20% over the period of a single decade, it is important that age be considered in nutritional evaluations based on anthropometric measurements. Changes in these four parameters with successive generations are also frequently large. Consequently, it is imperative that the reference values used in nutritional assessment protocols be updated at regular intervals.

Adipose Tissue↗

PubMed1998

Hematology and chemistry reference values for free-ranging harbor seals (Phoca vitulina) and the effects of hemolysis on chemistry values of captive harbor seals.

Most reported laboratory reference values for harbor seals (Phoca vitulina) are derived from captive seals, or stranded seals that have recovered from disease in marine mammal centers. This study established hematology and serum chemistry reference values for free-ranging harbor seals, using methods and that are current and readily available, and determined the effects of hemolysis on serum chemistry values of captive harbor seals. Blood samples were collected for hematologic and serum chemistry measurements from 14 clinically normal, adult male and female harbor seals and two juvenile harbor seals (approximate age 6 mo) captured in saltwater sloughs and estuaries near Moss Landing, California, USA. Values for amylase, globulin, and differential leukocyte count, not previously reported, were determined. In general, hematology and chemistry values in adults were similar to those reported for free-ranging and captive harbor seals, except for glucose, urea nitrogen, and lactate dehydrogenase (LDH) values, which were higher than those reported previously. Red blood cell counts in the two juveniles were higher than in adults and in young harbor seals studied previously. To determine the effects of hemolysis on serum chemistry values, two intensities of hemolysis were generated experimentally in blood collected from 11 harbor seals recovering from injuries or stranding at the Marine Mammal Center (Sausalito, California 94965, USA). Moderate hemolysis (++, 1 g/L hemoglobin, red-tinged) significantly increased LDH activity, whereas severe hemolysis ( , 2 g/L hemoglobin, cherry red) significantly increased total protein, albumin, calculated globulin, LDH, and total bilirubin and significantly decreased creatinine. The effects of hemolysis must be considered when chemistry results of harbor seals are interpreted.

Animals↗

PubMed2000

Population-based body mass index reference values from Göteborg, sweden: birth to 18 years of age.

UNLABELLED: The body mass index or BMI (weight/height2) is a somewhat crude estimate of nutritional status. However, due to its simplicity and high correlation with total body fat, it has been the method of choice in both paediatric clinics and research over the years. Since BMI is not an equivalent measure of the percentage of body fat in different ethnic groups and in the two sexes, population-specific BMI reference data is needed. Several BMI reference values have been published for French, American, British and Hong Kong children in recent years. In Sweden, weight-for-age and height-for-age reference values, which were published in 1976, are still used as the current national growth reference values. Updated growth reference values are needed for assessing nutritional status due to the secular trend toward and increasing prevalence of childhood obesity. The aim of this study was to produce BMI reference values for Swedish children of paediatric age. The series came from a large Swedish population-based longitudinal growth study of 3650 full-term babies followed from birth to 18 y of age. The children in this data set were born in the early 1970s. The pattern and level of 50th centile BMI values presented here are quite similar to those of the Swedish cohort study in the 1950s. In comparison with the US BMI reference values, the Swedish values are much lower, especially for the higher centile values. CONCLUSION: The new Swedish BMI chart from our study may provide a useful tool for paediatricians to assess body fat, and consequently nutritional status, in Swedish children.

Adolescent↗