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 91 records · Page 5Linked to original sources

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↗

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↗

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↗

PubMed1988

[Reference values for the maximal expiratory flow volume curve for adults. Results of a cooperative study].

Reference values of the maximal expiratory flow-volume curve for the adult GDR's population have been ascertained by a co-operative study of 5 lung function laboratories. We analysed measurements in 1,004 healthy subjects aged 16 to 69 years (728 males and 276 females). Prediction equations for the maximal expiratory flow rates, several time constants of lung mechanics and screening parameters of ventilatory inhomogeneity have been calculated by means of the multiple linear regression analysis. Our reference values are in good accordance with SEPCR summary equations. It is recommended to subtract from or add to the predicted values 1.64 standard deviations and to consider abnormal all values beyond this limit.

Adolescent↗

PubMed1985

[Microbiological reference values for food products].

This article describes the procedure recommended for setting up the ranges of microbiological reference values for foodstuffs, to be used in the microbiological inspection procedures of the integrated quality guarantee system. Such reference values should be based on 'Good Management Practices' (GMP) programmes. Strategic intervention, through control of the production line, in order to correct the contraventions evident in the GMP programme, is the first necessity in guaranteeing microbiological quality. Also, the hygienic/microbiological supervision of end products remains indispensible, so that the effectiveness of prevention procedures can be verified. In this way, errors which may have previously escaped detection can be found and eliminated. It is emphatically pointed out that only through cooperation between experts of various disciplines involved directly in animal health, working under one 'umbrella' organisation, can the best guarantee of efficacious protection be offered to the consumer.

Food↗

PubMed1985

[Factors influencing the diagnosis of lung function and our current reference values--results of the Pathophysiology of Respiration Society].

Reference values for lung function testing were determined of the spirometric volume and ventilation parameters VC, FEV1, RV (n = 3,750), bodyplethysmographic airway resistance and residual volume blood gases in rest (n = 5,779) and exercise (n = 117) considering the main influencing factors age, height, sex. The results were compared with international standards. Eleven laboratories of our country were engaged in examinations. The methods, the measuring conditions, the reference equations, and the valuation are described.

Adult↗

PubMed1988

Umbilical artery velocity waveforms: normal reference values for A/B ratio and Pourcelot ratio.

Normal reference values for the umbilical artery Pourcelot ratio and A/B ratio are reported. Thirty-five normal patients were studied serially from 20 weeks to term. The A/B ratio centiles were corrected for non-normality of the underlying distribution by transforming from the Pourcelot ratio values. The correction needed was small during the last trimester, but larger for second trimester data. Of the 35 patients 24 were nulliparous and there was a slight tendency for the waveform indices to be higher in the nulliparae, but the numbers in this study were too small to be conclusive about the effect of parity.

Blood Flow Velocity↗

PubMed1978

On establishing reference values.

In order to establish a range of reference values for any characteristic one can use Gaussian or nonparametric techniques, whichever are most appropriate. One has the choice of calculating tolerance intervals or percentile intervals. A tolerance interval is said to contain, say 95% of the population with probability, say 0.90. A percentile interval simply simply calculates the values between which 95% of the observations fall. If the data can be said to have a Gaussian distribution, the same precision can be obtained with smaller sample sizes than using the nonparametric techniques. In some cases, data which are not Gaussian can be transformed into a Gaussian form and hence make use of the more efficient Gaussian techniques. In both cases, the data should be checked for outliers or rogue observations and these should be eliminated if the testing procedure fails to imply that they are an integral part of the data.

Reference Values↗

PubMed1990

Blood ammonia concentration in mice: normal reference values and changes during growth.

To establish normal reference values of blood ammonia concentration in mice, possible factors which may affect blood ammonia determination such as age, sex, strain and sampling site of blood, were investigated by the microdiffusion method. The ammonia concentration in blood collected from the tail (mixture of venous and arterial blood) and left ventricle was significantly higher than that in venous blood collected from the orbital sinus and right auricle. Neither strain nor sex differences were observed. Blood ammonia concentration in newborn pups was 92 +/- 19 micrograms/dl immediately after birth and increased to 184 +/- 22 micrograms/dl 24 hours after birth. This increased level was maintained for a week. By 15 days, it decreased to the level at birth. Thereafter, no significant variation with age was observed. Blood ammonia concentration in mice after weaning, irrespective of age, sex and strain, varied from 38 to 123 micrograms/dl, with a mean +/- SD of 79 +/- 18 micrograms/dl.

Ammonia↗

PubMed1991

Doppler velocimetry: critical analysis of umbilical, cerebral and aortic reference values.

Cross-sectional reference standards of the umbilical flow velocity waveforms were investigated from 18 to 38 weeks of gestation on 482 normal pregnancies. A significant decrease in the pulsatility index (PI) and systolic/diastolic (SD) ratio was observed during gestation. This phenomenon was confirmed in a longitudinal study on 150 patients of the same population. The two slopes of cross-sectional and longitudinal data were not significantly different. A bimodal distribution of PI and S/D ratio was observed. Six per cent of data fell above the vast majority of cases. The dimension of the population studied allowed us to consider these findings not as outliers but as an interesting transient phenomenon of very low end-diastolic velocities which can occur in normal fetuses, without concomitant variations on the thoracic aorta and middle cerebral artery. Cross-sectional reference ranges were studied for these vessels on the same population from 26 to 38 weeks of gestation. A significant decrease in the PI of the middle cerebral artery was observed versus a significant increase in the PI of the thoracic aorta. These latter indices could be used to obtain indirect information on the normal redistribution of blood flow in the human fetus in the third trimester of gestation. However, the great variability observed should warn against the risks of a simplistic clinical use of these observations.

Aorta, Thoracic↗

PubMed1992

[Reference values for IgE concentration in serum of children. Method: ImmunoCAP-FEIA system].

UNLABELLED: Age specific IgE reference values were determined in serum of 224 children by the aid of the ImmunoCAP fluorescence enzyme immunoassay method. RESULTS: Cord blood: less than 0.35 kU/l; Till 0.5 year: less than 2.0 kU/l; 0.5-2 years: up to 3.8 kU/l; 2-5 years: up to 16.0 kU/l; 5-8 years: up to 26.2 kU/l; 8-12 years: up to 34.6 kU/l; 12-16 years: up to 26.3 kU/l. These IgE reference values can be used for the diagnosis of pathological elevated IgE concentrations in serum of children.

Adolescent↗

PubMed1991

Reference values in the nineties: from theory to practice?

Following a brief summary of the published documents on the theory of reference values, the reasons for the still limited practical implementation of the theory itself in clinical laboratories are discussed. It is suggested that cooperative efforts could overcome the difficulties in obtaining an adequate reference sample group, provided that some basic requirements are strictly fulfilled, such as the stability and the homogeneity of the analytical quality and of the reference population. Banks of biological materials will further reduce the complexity and the cost of production of reference values.

Chemistry, Clinical↗

PubMed1989

Clinical reference values for serum protein electrophoresis for the llama (Lama glama).

Serum protein electrophoresis was performed on 71 clinically healthy juvenile and adult llamas (6 juvenile males, 7 juvenile females, 25 adult males, 13 adult females, and 20 pregnant females) to determine normal serum protein concentrations. Values were reported for each of the 5 groups because the groups were not homogeneous in all 8 peaks. Although the values reported here may serve as reference values for adults, they represent only a guideline for the juveniles because of the limited number of animals in each of these groups.

Animals↗

PubMed1992

Reference values for chromosome aberrations in human lymphocytes as indicators of genotoxic effects.

Increased chromosome aberrations (CA) in human cultured lymphocytes are an accepted indicator of early biological effects of exposure to genotoxic agents, which has also been investigated, with conflicting results, in several groups of subjects occupationally exposed to metals known or suspected to be carcinogenic. One of the problems with this indicator is the lack of universally accepted reference values. Difficulty in establishing absolute reference values for CA depends on individual variability in the reference groups (due to several environmental and genetic confounding factors) and on methodological variants at the different stages of the test (culture methods, scoring, classification and reporting of CA). Therefore, at present, CA studies in exposed groups should include proper 'control' groups, matched for the known confounders, investigated in the same laboratory, with the same methods in order to minimize factors of variation. The results of the studies should be statistically compared and evaluated mainly on a group basis.

Carcinogens↗