PubMed Health⌕ Search

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 109 records · Page 6Linked to original sources
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↗
PubMed1980

Effects of posture on concentrations of blood constituents in healthy adults: practical application of blood specimen collection procedures recommended by the Scandinavian Committee on Reference Values.

Different procedures for the collection of blood for the determination of reference values in healthy adults have been subjected to practical testing. The Scandinavian Committee on Reference Values suggested that subjects lying in bed after an overnight sleep and ambulatory individuals, after 15 min of sitting in a chair, were two suitable and different reference populations. In forty subjects we found an increase from lying to sitting position of about 6.5% in the serum concentrations of proteins, enzymes and lipids. The corresponding increases for S-calcium and B-haemoglobin were approximately 3% whereas S-thyroxine, unexpectedly, changed by 11%. There were no significant changes of potassium and sodium values. For some constituents the changes were age and sex-dependent being greater in a group of elderly women as compared to a group of younger men. After 1 h of recumbency the concentrations of the constituents generally returned to those in the initial, lying position.

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↗
PubMed1981

[Reference values for 2 well-defined populations: newborn infants and post-partum women].

Reference values for two well defined populations, four day old newborns and post-partum women, are given for 19 parameters measured on a SMAC system. These values are respectively compared to those established previously for children from one to three year old and those of women aged 20-39. The values for the new borns are higher for eight parameters and lower for nine others. The values for post-partum women are higher for seven parameters and lower for six others. These two groups have therefore distinct reference values for most of the parameters studied.

Adult↗
PubMed1989

Criteria for reference value assessment of elements in human tissues.

The availability of updated and reliable reference values for elements in biological tissues and fluids plays a key role in the correct planning and performance of clinical, toxicological and environmental studies. The basic principles for a proper analytical approach in order to obtain such data are outlined. This in turn should significantly reduce the wide range of figures reported for most elements as "normal" intervals in the scientific literature. Some applications of these guidelines are illustrated in detail in the case of human lungs, liver and kidneys for which tentative reference values are assessed for a number of minor and trace elements, namely, Al, Ba, Cd, Cr, Cu, Li, Mg, Mn, Pb, Sr, V and Zn.

Humans↗
PubMed1995

Reliability and adequacy of discharge diagnosis databases in the production of reference values.

Discharge diagnoses provide a possibility to select patients individually and then to establish reference values for both "pathological" and control groups. Currently, the available diagnostic information is still at its infancy and should be carefully evaluated before the reference values based on those groups are utilized. It is anticipated that electronic storage of diagnostic and therapeutic information will be applied more commonly in the future as the development of computers makes it easier. The advanced utilization of laboratory data challenges physicians both in the clinical and laboratory side to participate in this development in order to make the information systems serve their actual needs more closely.

Clinical Laboratory Information Systems↗
PubMed1988

Methods for measurement of muscle function. Methodological aspects, reference values for children, and clinical applications.

In children isometric muscle force can be measured with acceptable reproducibility by using a simple hand-held dynamometer. Reference values for 10 different muscle groups are given for children aged 3.5-15 years. If age and weight are known, the force can be predicted. The most pronounced differences between the dominant and the non-dominant side were found in the elbow flexors, 3 of the 6 age groups showing greater force on the dominant side, and in the wrist extensors, the 2 oldest age groups being stronger on the dominant side. Sex differences were present as early as 9.5-11 years of age, boys being stronger than girls. Isokinetic muscle torque of the dorsiflexors of the ankle increased with age. Reference values are given for peak torque in children 6, 9, 12, and 15 years of age. The most intense force development occurs between 12 and 15 years of age in boys, and earlier in girls. Sex differences appear in early puberty. In young children the dominant leg was the stronger at the highest velocities. In the older children the non-dominant leg was the stronger at low velocities. Isokinetic measurements are time-consuming and require experience, and should be regarded as complementary to isometric testing. In muscle groups that are too weak to overcome gravity isometric and isokinetic methods cannot be used. Functional tests of motor ability are especially useful in patients with severely impaired muscle function when other test methods are inadequate or difficult to evaluate. The natural course of Duchenne muscular dystrophy was followed in 16 boys by means of functional tests, isometric tests, isokinetic tests of concentric muscle contraction, and manual tests. Of these only the isokinetic method proved unreliable, possibly because of difficulty in activating the muscles at different speeds. The function of adductor pollicis was studied by supramaximal electrical stimulation of the ulnar nerve. Force-frequency curves and reference values for relaxation rate and half contraction time to tetanus for children aged 9, 12, and 15 years are presented. The half contraction time to tetanus was briefer in the older children than in the younger. The relative force developed at a stimulation of 10 Hz increased with age. Apart for the increase in muscle force with increasing age, no other differences emerged between the different age groups. No sex differences were found. The electrical stimulation test is rather painful, and only about 60% of the children persevered to the end of the test.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Reference values for serum components in pregnant women.

Reference values have been collected for 11 chemical blood serum components during the three trimesters of pregnancy in 100 healthy pregnant women. The results used for reference intervals are presented as 2.5, 50 and 97.5 percentiles. Especially regarding S-Albumin, S-Alkaline phosphatase and S-5'-Nucleotidase the changes were most pronounced during the third trimester. S-Gammaglutamyl-transferase did not change significantly during pregnancy. For S-Aspartate aminotransferase and S-Alanine amino-transferase there were no significant changes in the mean values during the three different trimester periods. In the third trimester the frequency distribution of the enzymes became skewed to the right, i.e. in some women the enzyme activities increased noticeably more than in others. S-Na showed a significant decrease even during the first trimester and this lowering was slightly more pronounced during the second and third trimesters. S-Ca decreased in parallel with S-Albumin concentration. The changes in S-CaAlbumin-corrected were distinctly smaller than those in S-CaTotal. Throughout pregnancy, S-K, S-Bilirubin and S-Thymol turbitidy test values did not deviate from non-pregnant levels.

Adolescent↗
PubMed1981

[Reference values for a new alpha-amylase determination in serum and urine (author's transl)].

Reference values for a new alpha-amylase estimation using maltoheptaose as substrate were determined in 251 healthy men and women in serum at 25 degrees C and at 30 degrees C and in urine at 25 degrees C. Sex dependency was not demonstrable. The following reference ranges are suggested: 30-100 U/l in serum at 25 degrees C, 40-130 U/l in serum at 30 degrees C, and 500 U/l in urine at 25 degrees C. In addition reference values for the relative percentual amylase-creatinine clearance (25 degrees C) of 0.25-4% and for amylase activity per mg creatinine (urine 25 degrees C) of 0.02-0.25 U/mg creatinine are suggested.

Adolescent↗
PubMed1985

Time domain spirogram indices. Their variability and reference values in nonsmokers.

A cross-sectional population survey of dynamic ventilatory lung function was performed to determine the variability of and reference values for time domain spirogram indices. The reference population comprised 83 men and 143 women who were healthy nonsmokers. The time domain indices were derived from the blow with the largest sum of FVC and FEV1. Prediction equations for FEV1 and mean flow between 25 and 75% FVC were little influenced by methods for selecting the data from the 3 blows recorded. The variability of the first 2 moments of the spirogram increased with age, requiring a log transformation for regression analysis. Prediction equations for conventional and time domain spirometric indices are presented and reference values are proposed based on an estimated percentile derived from the predicted value and the residual standard deviation from regression. Two time domain indices are identified that may prove better suited than conventional indices for identifying abnormalities in the tail of the spirogram.

Adult↗