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PubMed1986

Pediatric reference values for calcium, magnesium and inorganic phosphorus in serum obtained from Bhattacharya plots for data from unselected patients.

Pediatric reference values for total calcium, magnesium and inorganic phosphorus are given. The values were determined by using Bhattacharya plots for unselected data. The reference values for calcium (from 8320 values from patients) and magnesium (from 1231 values from patients) show only minor dependence on age. Reference values for ages up to 20 years for calcium were 2.14-2.64 mmol/l and for magnesium 0.57-1.12 mmol/l. However, for inorganic phosphorus (3349 values from patients) a gradual decrease in concentration occurred throughout childhood from 1.56-2.29 mmol/l (less than 1 year) to 1.03-1.78 mmol/l (greater than 15 years).

Adolescent↗
PubMed1989

[Aging and reference values of the parameters in optokinetic nystagmus].

Changes in optokinetic nystagmus by age were assessed, and preparation of reference values by age was made by the use of the data from 834 reference subjects. As a result, changes by age were observed at the test on optokinetic nystagmus. The reference values by these changes can be approximated with the quadratic and was considered, therefore, to be useful clinically. Four parameters were set for the test items for optokinetic nystagmus as the total number of nystagmus (NYS); the mean of eye velocity during the fast phase of nystagmus (FM); the algebraic summations of eye velocity (VEL) and amplitude (AMP) during the slow phase of nystagmus. As the process for statistical analysis, variables were divided into 7 groups, and after removing outlier (any extraneous data) in each group, changes in variables by age were assessed by the one-way analysis of variance and the method of multiple comparison (Ryan's method). As a result: 1) the age group of each variable seemed to develop into normal distribution; 2) it was presumed that change in NYS by age is less; 3-1) regarding FM, VEL and AMP, no change was observed in the variable by ages on 30s and 40s; and 3-2) however, decrease in the measured value was observed in ages on 60s along with aging. From these, the ages on 50s are the generation when the measured values of optokinetic nystagmus change. On the other hand, the reference values calculated, taking age into consideration, could be approximated with the quadratic.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Calculation of reference values for lung function tests.

The powerful computers that are now available enable calculation of reference values by endless permutations of regression models that are not always biologically meaningful. The aim of this study was to test the ability of simple regression models to describe data that has been collected for calculation of reference values. Healthy non-smoking females (n = 74) and males (n = 51) were studied with 22 commonly used lung function tests. If the data were logarithmically transformed, there was a satisfactory reduction of residual variation and the assumption of normality was fulfilled. Furthermore, the difference between males and females could be described by a binary sex-variable that is independent of interactions with other variables such as age, height and weight. Logarithmic transformation of lung function measurements followed by linear regression is recommended as a simple standard method for calculation of reference values.

Adult↗
PubMed1985

Smoothing techniques for obtaining reference values for measurements of children.

Constructing reference values for measurements of children, e.g. the mean height as function of age, one needs a smoothing technique. Various techniques will be discussed and applied to a particular study of anthropometric growth. The overall conclusion is that reliable curves can be obtained by using computer programs based on approximations by cubic splines, and by using the eye for choosing from the corresponding outputs.

Adolescent↗
PubMed1983

[Concentration levels of thyroxine binding globulin and thyroxine in the blood of euthyroid children. Reliability and diagnostic value of the T4/TBG quotiens--establishing reference values].

The most important transportprotein for thyroxine (T4) is the thyroxine-binding globulin (TBG). This protein and T4 were determined using the radioimmunoassay method in bloodserum of 443 euthyreotic children. The age-specific analysis showed high TBG and T4 concentrations in the postnatal phase, nearly constancy between 1. and 9. years with concentrations in the upper physiological range of adults, elevation of the values in the age of 10/11. years and definite attainment of the normal range for adults at 12/13. years. The importance of the T4/TBG quotient for thyroid gland diagnostics was discussed.

Adolescent↗
PubMed1987

The determination of reference values for hematologic parameters using results obtained from patient populations.

Reference values for hematologic parameters are determined using data from patient populations of a whole year. As a consequence, the authors are not dependent on a limited selected population and can determine reference values for all age and sex groups. It turns out that from the possible compilation technics the gamma distribution gives the best fit. If the results are compared with values stated in the literature, it is remarkable that the total number of leukocytes for men older than 50 years is higher than for women; both the absolute and relative amount of monocytes and eosinophilic granulocytes are higher for men than for women. The platelets are lower for men than for women from the age of 15 years on.

Adolescent↗
PubMed1988

Age-related reference values for ionized calcium in the first week of life in premature and full-term neonates.

Reference values for ionized calcium were measured in anaerobic samples of capillary blood from 22 healthy premature neonates, gestational age 33-36 weeks, birth weight 1660-2480 g. Reference values (mean +/- 2SE) for premature neonates aged 5-12, 13-19, 25-48, 51-72, 77-99, 108-140, 150-185 h were: 1.21 +/- 0.16, 1.17 +/- 0.12, 1.21 +/- 0.16, 1.28 +/- 0.18, 1.34 +/- 0.14, 1.38 +/- 0.13, 1.40 +/- 0.16 mmol/l, respectively. Ionized calcium in 59 full-term neonates with mild pathological hyperbilirubinaemia (no phototherapy needed) and 28 neonates born by section (no neonatal complications) showed no statistical difference (unpaired t-test) in age-related values compared with matching healthy neonates with no clinical remarks. Data for full-term neonates were pooled and age-related reference values (mean +/- 2SE) for ionized calcium in capillary whole blood for 168 full-term neonates, gestational age 38-41 weeks, birth weight 2550-4700 g, aged 1-12, 13-24, 25-48, 49-72, 73-99, 99-120, 121-144, 146-168, 178-264 h were: 1.24 +/- 0.11, 1.19 +/- 0.12, 1.21 +/- 0.13, 1.22 +/- 0.14, 1.29 +/- 0.17, 1.35 +/- 0.12, 1.37 +/- 0.12, 1.38 +/- 0.16, 1.40 +/- 0.10 mmol/l, respectively.

Age Factors↗
PubMed1987

Clinical chemistry reference values in two breeds of swine and their changes during percutaneous exposure to soman.

Clinical chemistry reference values in blood from 48 nonfasting Chester White/Yorkshire and 48 Hanford Miniature swine were determined. Subsequently, 40 animals of each breed were restrained in a cloth sling and fasted for 24 hours while exposed percutaneously to pinacolyl methylphosphonofluoridate (soman). The range of dosages for the Hanford Miniature swine was 2.0 to 15.8 mg/kg, and for the Chester White/Yorkshire swine, the range was 4.0 to 25.0 mg/kg. Sham-exposed groups, consisting of 8 animals of each breed, were treated in an identical manner, except no anticholinesterase agent was administered. Samples of blood were drawn at 1, 7, 14, and 28 days after soman or sham exposure. In the sham-exposed groups, significant changes from the reference values were observed as a result of the 24-hour restraint. In both breeds, skeletal muscle enzyme activities were increased, plasma cholinesterase activity (ChEPL) was decreased, calcium concentration was decreased, and phosphorus concentration was increased. Percutaneous exposure to soman resulted in decreases of ChEPL and erythrocyte cholinesterase activities (ChERBC). The ChEPL recovered more quickly than the ChERBC in both breeds. Even in asymptomatic swine, the decrease of ChERBC was greater than 60% after 24 hours. In the swine of each breed given the largest dosage, hyperglycemia was apparent in blood samples taken at the onset of apnea, especially when the animal survived for greater than 2 hours. We conclude that both breeds of swine, on the basis of dispersion in clinical chemistry reference values, were equally suited for this type of dermatotoxicity study. The sling method of restraint, however, caused some undesirable changes in biochemical values.

Animals↗
PubMed1991

A study of peripheral diabetic neuropathy. The application of age-related reference values.

The standardization of methodology and the provision of age-related reference values have been addressed for the design of and interpretation of data from a multicentre neuropathy trial. Age-related reference values were generated from 120 healthy volunteers. Vibration perception thresholds (VPT) deteriorated significantly with age (p less than 0.001). Patients were selected on the basis of age-related abnormal VPT and peroneal motor nerve conduction velocity. They were assessed at the beginning and end of a placebo run-in period (baseline data). The coefficients of variation (CV%) for VPT at the medial malleolus (16.81 per cent, n = 316) and great toe (19.23 per cent, n = 313) were lower compared to results in healthy volunteers (29.7 per cent and 20.8 per cent, respectively, n = 49). The CV% for expiratory:inspiratory (E:I) ratio (4.82 per cent, n = 215), Valsalva manoeuvre (10.84 per cent, n = 249) and 30:15 ratio (7.73 per cent, n = 292) from patients corresponded to those recorded in volunteers (7.6 per cent, n = 45 11.0 per cent, n = 49 9.5 per cent, n = 48, respectively). Most patient values for VPT at the great toe fell beyond the 95 centile line for volunteers. E:I ratio for volunteers showed a more variable relationship with age, although patient values appeared to be located below the 5 centile line for volunteer data.

Adult↗
PubMed1991

Cardiovascular autonomic reflex tests: normal responses and age-related reference values.

One hundred and forty-three healthy unmedicated subjects from a random sample, aged 20-80 years, were examined and cardiovascular autonomic function tests (Valsalva manoeuvre, deep and quiet breathing tests and active orthostatic test) were performed in order to study normal responses to these tests and to determine age-related reference values. Most of the cardiovascular indices reflecting autonomically mediated heart rate responses decline with advancing age and this leads inevitably to the need for age-related reference values. The indices are in general independent of sex but most indices are dependent on resting heart rate. The inter-individual variation is very marked so that the normal ranges are wide, and because the indices diminish with age, the lower reference values are less suitable for use in aged subjects. The reference values make it possible to use the indices for diagnostic purposes in young and middle-aged subjects (up to 65 years), whereas in older subjects the indices can be used in order to exclude autonomic disturbances. Reproducibility of heart rate indices is satisfactory or good whereas reproducibility of blood pressure indices is poor.

Adult↗
PubMed1987

Highly sensitive assays of serum-thyrotropin in the diagnosis of hyperthyroidism: assessment of performance and reference values.

The performance of three different highly sensitive immuno-assays for thyrotropin in serum (S-TSH) was compared. Specimens from 803 patients with suspected hyperthroidism or other thyroid disease were used. Hyperthyroid patients were identified and characterized by determining serum thyroid hormones and by clinical observation. The performance of the methods in discriminating between hyperthyroidism and euthyroidism was described in terms of diagnostic sensitivity and specificity. The performance was also assessed by systematically varying the reference values. If patients with treated hyperthroidism were eliminated, the three S-TSH assays performed equally well at a suggested lower reference value of 0.4 mU/l. A diagnostic efficiency of more than 0.95 was achieved at the observed prevalence of disease (0.12). A graphical model which allows an adjustment of reference values to favour sensitivity or specificity is presented. Reference values were also calculated from the euthyroid subjects using parametric and non-parametric approaches. The specificity, when using the recommended discrimination level, suggests that patients with low S-TSH values should be subjected to further investigation by biochemical or other methods.

Adolescent↗
PubMed1992

Definition of reference values for Cd-B and Cd-U: methodological aspects and preliminary results.

In the present study, a definition of the reference values of blood cadmium (Cd-B) and urinary cadmium (Cd-U) was attempted, adopting the same methodology as that used for Hg-B by ICOH and IUPAC. Papers published from 1976 onwards were reviewed. The majority of the studies were concerned with the formation of control groups for toxicological and epidemiological investigations rather than with the definition of reference values. Since the number of subjects for whom data on cadmium were available was small, only the data on Cd-B were considered. After evaluation, only four studies were found to be suitable for the establishment of tentative reference values for Cd-B. It is essential in all such studies to check the statistical and analytical methods for correctness, and the case-list must be selected taking smoking into account as the main interfering factor. It was found that Cd-B values show less dispersion when geometric means and standard geometric deviations are used instead of arithmetic means and standard deviations.

Cadmium↗
PubMed1992

[Establishment of reference values for fructosamine and HbA1c in childhood].

Reference values for fructosamine and glycated haemoglobin in children are still lacking. Using samples from 522 children (age range 1 day to 9 years), plasma electrophoresis was performed, fructosamine and total protein were determined in EDTA-plasma, and glucose and the fraction of glycated haemoglobin (HbA1c) were determined in EDTA blood. The results were grouped according to age (1, 3 and 5 days, 6-28 days, 2-12 months, 2-3 years, 4-6 years, and 7-9 years). Differences between the age groups were determined using the Mann-Whitney-U-test, and the values in each group were summarized where possible. The 95%-interval was calculated for fructosamine, protein-corrected fructosamine, and HbA1c.

Child↗
PubMed1986

Hematology and biochemistry reference values for the ranch fox.

Reference hematology and biochemistry values are presented from a mixed population of 30 silver and red foxes of both sexes, reared and living under fox-farming conditions in southern Ontario. Based on history and physical examination, the animals in this study were clinically healthy at the time of blood collection and maintained under similar husbandry practices. The observations were examined for outliers and Gaussian distribution before and after one of three transformations. Parametric analysis was used to determine lower and upper reference limits. Where observations were not Gaussian, minimum and maximum values are given. These reference values are presented as a usable first approximation of population reference values to assist clinicians and researchers in their interpretation of observations obtained from foxes of similar populations.

Animals↗
PubMed1986

Hematology reference values for peripheral blood of laboratory rats.

Reference values for peripheral red and white blood cells, platelets and coagulation parameters from 11 and 18-week-old Charles River Sprague Dawley rats [Cr1:COBS CD(SD)] were obtained using automated methods. The Coulter Model S Senior, the Clay Adams Ultra-Flo Platelet Counter and the Sherwood Lancer Coagulyzer, were used to measure these parameters on 25 rats/sex. Detailed information on instrumentation or assay methods, and the animals, their source, environment and blood collection method was given. Platelet counts were in the range of 694 X 10(9)/1 to 1412 X 10(9)/1 which was higher than previously reported. In general, the remaining ranges were similar to previously published reference ranges.

Animals↗
PubMed1990

[Age dependence, sex independence and reference values of serum fructosamine determined using a new colorimetry method].

Reference ranges were evaluated for a new colorimetric method for the determination of fructosamine in serum. The reference group was composed of 1114 non-diabetics of both sexes including children. Reference values are only slightly affected by age and sex. In the course of childhood to adolescence fructosamine values raise and finally stabilize in adults. The small differences between both sexes have no effect on the interpretation of clinical results. Relating fructosamine values to albumin or total protein has little impact on the distribution of the values when protein values were within the reference range.

Adolescent↗
PubMed1992

Trace element reference values in tissues from inhabitants of the European Community. II. Examples of strategy adopted and trace element analysis of blood, lymph nodes and cerebrospinal fluid of Italian subjects.

The EURO TERVIHT (Trace Element Reference Values in Human Tissues), recently initiated, aims to establish and compare trace metal reference values in inhabitants from the different EC countries. The project anticipates international cooperation of specialized chemical and toxicological laboratories in Western Europe. In order to overcome the well known and intolerable high fluctuation in published trace metal concentrations in body fluids and tissues, which are mostly due to poor analysis, this paper gives recommendations and strategies for approaching 'background' values measurement practised in the EURO TERVIHT. The focus of the paper is more on quality rather than on quantity of data with particular aspects: (i) well-described protocol for the selection/composition of reference groups (extended epidemiological data plus clinical status); (ii) numerous pre-analytical factors, among which are of paramount importance are ultraclean laboratory air, container material, storage conditions at -20 degrees C; (iii) statistical treatment of the data and the expression of the analytical results (use of refined statistical analysis such as the Lilliefors test to define the type of distribution, normal or log-normal). Results reported here concern the determination of trace elements in whole blood of more than 350 Italian subjects which allowed the proposal of 'reference values' for 12 elements. In lymph nodes and cerebrospinal (CSF) the degree of information acquired is only sufficient to suggest 'indicative' of 'informative' values.

Computers↗