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PubMed1989

Reference values for resting blood flow to organs of man.

The lack of a reliable quantitative description of blood flow in man has hampered the development of accurate biokinetic models of essential elements, drugs, imaging agents, and carcinogens. In this paper we review and analyse data on blood flow and identify representative percentages of cardiac output and absolute blood flow rates to organs and tissues of man for use as reference values for biokinetic models. To keep the review and analysis to a manageable size we have limited attention to the resting state and have suggested reference values for absolute and relative flow rates only for adult males and females.

Adult↗
PubMed1990

Reference values of magnesium and potassium in mononuclear cells and erythrocytes of children.

Reference values for magnesium and potassium contents of mononuclear cells and erythrocytes were estimated in cord blood and in children from infancy through adolescence. No differences were detected between results for boys and girls. The mononuclear magnesium content was independent of age and was within the adult range of values. No significant correlation was shown between magnesium in serum and in mononuclear cells. Mononuclear potassium also showed no age-related differences. The correlation between magnesium and potassium contents in mononuclear cells was significant: however, the correlation was lower when the magnesium and potassium contents were expressed in terms of protein potent: micromoles or millimoles per gram of protein, respectively. The concentration of magnesium in erythrocytes was significantly lower in cord blood and during the first month of life, compared with that at older ages, and showed no significant correlation with serum magnesium. The concentration of erythrocyte potassium was independent of age and showed a low but significant correlation with erythrocyte magnesium content.

Adolescent↗
PubMed1979

[Creatine kinase: reference values and clinical aspects of the revised standard method (author's transl)].

Reference values for the revised standard method for determining N-acetylcysteine (NAC) activated creatine kinase (CK) activity in serum are presented, based on samples from 432 out-patients and 423 in-patients of either sex. CK activity was not age-related. The suggested range of normal values for serum CK activity, measured by the revised standard method at + 25 degree C, is 10--70U/l for females and 10--80U/l for males. Where an elevation of serum CK activity is of uncertain cause, the CK/GOT ratio had been recommended, additional to the CK-MB isoenzyme, for distinguishing between damage to heart and skeletal muscle. The significance of this ratio was checked with the revised standard CK method and the optimized GOT determination. The point of separation between myocardial and skeletal muscle damage is 10 by this methods. In order to use this ratio, total CK activity must be over 150 U/l and liver disease or secondary liver involvement must have been excluded. The CK/GOT ratio gains in importance through findings which limit the specificity of CK-MB as a purely myocardial (infarct)-specific isoenzyme.

Adolescent↗
PubMed2002

[Reference value and cut-off value for diagnosis of insulin resistance in type 2 diabetes mellitus].

The homeostasis model assessment-insulin resistance(HOMA-IR) index has been proposed to assess insulin resistance, which plays an important role in the pathogenesis of type 2 diabetes mellitus. However, it has not generally introduced into the outpatient care in Japan, because of lack in definite reference values. In this paper we studied the precision in the assay of immuno-reactive insulin and then the HOMA-IR index was determined in 90 healthy individuals and 281 type 2 diabetic patients. The reference value was calculated to be 1.77 +/- 0.44(mean +/- SD) in healthy individuals without obesity. Receiver operating characteristic curve analysis gave the cut-off values discriminating between healthy and diabetic subjects to be 2.53, 3.50 and 3.00 in non-obese, obese and total individuals, respectively. These values should be available for the diagnosis of insulin resistance in type 2 diabetes mellitus.

Adult↗
PubMed1995

Reference values of pulmonary diffusing capacity during exercise by a rebreathing technique.

Normal reference values of the pulmonary diffusing capacity for carbon monoxide (DLCO), diffusing capacity of the membrane (DMCO), and pulmonary capillary blood volume (VC) were derived by a rebreathing technique in 44 normal, healthy, nonsmoking individuals ranging from 17 to 68 yr of age. Simultaneous measurements of DLCO, lung volumes, pulmonary blood flow, and septal tissue volume were determined at rest and during steady-state exercise of 25, 50, and 80% of maximal workload and at two levels of alveolar O2 tension. DMCO and VC were calculated using the Roughton-Forster relationship. Using stepwise regression analysis, DLCO and DMCO (in ml CO/min/mm Hg) were found to be significantly related to pulmonary blood flow (Qc in L/min), age (in years), and body surface area (BSA in square meters). VC (in ml) was found to be significantly related to QC and BSA. Normalization of measured data with respect to these variables largely eliminated male versus female differences. We conclude that QC is the most important determinant of the recruitment of diffusing capacity. From rest to near-maximal exercise, DLCO, DMCO, and VC increase linearly with respect to QC without evidence of reaching a plateau.

Adolescent↗
PubMed2003

Reference values for the physical work capacity on a bicycle ergometer for men -- a comparison with a previous study on women.

The aim of the study was to collect new reference values for the clinical ramp exercise test on bicycle, because in our experience, the commonly used values were too low. A group of healthy men (n = 81, 20-80 years) was randomly selected from the local municipal register to achieve an even distribution in age. Data were compared with those obtained in a similar, previous study on women (n = 87). The subjects were encouraged to cycle until exhaustion (19 on the Borg scale) when maximal load, heart rate and systolic blood pressure were recorded. Maximal load (W(max)) was related to age (years) and height (m) using a non-linear function: W(max) = (244.6 x height - 92.1)/[1 + exp[0.038 x (age - 77.3)]]. Maximal heart rate (HRmax) was described by a similar function: HRmax = 203.7/[1 + exp[0.033 x (age - 104.3)]]. The maximal systolic blood pressure (BP(max)) was described by a linear function based on age: BP(max) = 0.505 x age + 192. Similar functions for the women are also given. It is suggested that 80-120% of the predicted maximal load can be taken as a reference interval for both men and women and similarly 90-110% of the maximal heart rate. In this study, 84% of the men reached a maximal load within the reference interval and 93% maximal heart rate within the reference interval. The reported values for maximal load were 104-132% of the reference values published by others.

Adult↗
PubMed2004

[Comparison of spirometric reference values in Chilean children].

BACKGROUND: The interpretation of lung function tests must be based on reference normal values obtained in the same population. In Chile an expert panel recommended the use of values obtained by, Gutierrez el al locally, that are higher than those obtained by Knudson, for forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1). AIM: To analyze the clinical application of both reference values in a selected population. MATERIAL AND METHODS: Retrospective review of 499 spirometries done in our laboratory to 285 males and 214 females, aged 4.5 to 18 years. The reports using either Gutierrez (G) or Knudson (K) reference values were compared. The 5th percentile was considered the inferior limit for normality. RESULTS: The height range of patients was 110-178 cm (median 130, 3rd quartile 143). Referral diagnoses were probable asthma in 349 (70%), asthma in 119 (24%), to rule out restrictive disease in 12 (2%) and others 19 (4%). FEV1/FVC ratio was > or =84% in 290 patients. Using K values, lung function was interpreteed as within normal limtits in 321 patients (64.3%), as mild obstructive disease (MOD) in 171 (34.3%), as combined limitation (CL) in 2, mild restrictive disease (MRD), moderate restrictive disease (MR) and severe restrictive disease (SRD) in 1 patient each. Using G values, lung function was interpreted as within normal limits in 133 patients (26.7%), MOD in 343 (68.7%), MRD in 6, CL. in 4 and MR in 2. In 193 spirometries (39%) there was lack of concordance between the interpretations using K or G values. CONCLUSIONS: There is a wide rante of variability when G or K values are used to interpret lung function in children in Chile. Redefinition of local standards would be necessary.

Adolescent↗
PubMed1997

Serum boron concentration from inhabitants of an urban area in Japan. Reference value and interval for the health screening of boron exposure.

Boron (B) levels were determined in the serum of 980 healthy inhabitants living in an urban area of Japan by means of inductively coupled plasma emission spectrometry (ICPES). The results showed a log-normal distribution of serum B for both sexes, although there are age-related differences. In male subjects, serum B increases rapidly up to 49 yr of age, reaching a plateau between ages 50 and 69 yr old, followed by a gradual increase up to 70 yr or older. Female subjects exhibit a gradual increase up to the age of 70 yr old. The reference value for male and female subjects was 79.8 micrograms/L and 67.9 micrograms/L, and the reference interval was 33.3-191.2 micrograms/L and 29.5-154.9 micrograms/L, respectively. The obtained reference value and interval of the nonexposed group may be useful for health screening for B exposure, either for people living in regions with high levels of B in the environment, or for workers who are exposed to this element.

Adolescent↗
PubMed1997

Age-specific reference values for serum prostate-specific antigen in a community-based population of healthy Swedish men.

To establish normal reference values for prostate-specific antigen (PSA) in a Swedish population we investigated 878 healthy men, 56-75 years of age. They were randomly selected from a population of 9171 males in this group. Cancer of the prostate was excluded by digital rectal examination. When digital rectal examination was suspicious for carcinoma of the prostate and/or serum PSA > 4 micrograms l-1, fine-needle aspiration biopsy was performed. Central values, values of variance and reference limits were defined by a non-parametric method in four age groups. A strong positive correlation between PSA values and age was found and the variance increased with age. The relationship between PSA value and age was non-linear. For the age group 56-60 the upper reference limit (95th percentile) was 4.6 micrograms l-1 (confidence interval, CI: 3.9-5.5). For the age groups 61-65, 66-70 and 71-75 the corresponding values were 4.4 (3.8-5.2), 7.6 (6.5-8.9) and 8.4 micrograms l-1 (7.2-9.8) respectively. For the age groups studied the increment over time of the PSA value was 2-8% per year depending on age, with an average increment per year over 15 years of 4.3%. Overall, 11% of our reference sample had a serum PSA level > 4 micrograms l-1. We consider our study population to be representative for a normal Swedish male population in these age groups.

Aged↗
PubMed1998

References values for forced spirometry. Group of the European Community Respiratory Health Survey.

The European Coal and Steel Community (ECSC) prediction equations exemplify a significant effort carried out approximately 15 yrs ago to provide uniform standards for lung function testing, but this set of equations has not been properly validated as yet. The present study evaluates the ECSC reference values and four other sets of prediction equations, using spirometric data collected in 12,900 nonasthmatic subjects (43% lifetime nonsmokers and 36% active smokers) aged 20-44 yrs from the European Community Respiratory Health Survey (ECRHS). Standardized spirometric measurements were obtained using a common protocol in 34 centres in 14 countries. For each prediction equation, the prediction deviations (i.e. observed minus predicted value) for forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were examined for the whole study population and for each centre. For the age range included, the errors about the ECSC equations showed the most prominent underestimation of both predicted FVC (+355 and +360 mL on average in males and females, respectively) and predicted FEV1 (+211 and +200 mL, respectively) among the five studies examined. As expected, FVC and FEV1 in active smokers from the ECRHS were significantly lower than in lifetime nonsmokers (each p<0.01). We conclude that the present European recommendations on lung function reference values should be reconsidered, but further data for nonsymptomatic subjects above the age of 44 yrs are needed.

Adult↗
PubMed1999

Reference values for vertebral artery flow volume by duplex sonography in young and elderly adults.

BACKGROUND AND PURPOSE: Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume, the product of mean flow velocity and the cross-sectional area of the vessel. It can be determined by duplex sonography. There are no reference values for vertebral artery flow volume in an age group representative of patients with cerebrovascular disease. METHODS: We examined 50 nonvascular neurological patients (age 55.8+/-14.0 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segments bilaterally, and the flow volume was calculated according to the following equations: (1) Q1=time-averaged mean velocity times area and (2) Q2=(time-averaged maximum velocity/2)times area. RESULTS: Flow velocities and vessel diameters tended to be lower on the right side, resulting in a lower flow volume. Flow volumes (according to Equation 1) were 77.2+/-29.8 mL/min on the right side, 105.3+/-46.4 mL/min on the left side, and 182.0+/-56.0 mL/min net. Side-to-side differences were not significant. Flow volumes calculated with the 2 equations did not differ significantly. An age dependence could not be shown, but vessel diameters and net vertebral artery flow volumes were significantly lower in women than in men. The normal range for net vertebral artery flow volume defined by the 5th to 95th percentiles is between 102.4 and 301.0 mL/min. This wide range is due to the high interindividual variability of the parameters. CONCLUSIONS: On the basis of the reference values presented here, the association of decreased vertebral artery flow volume and vertebrobasilar ischemia should be reevaluated. Additional areas for investigation include the quantification of collateral flow in the vertebral arteries in carotid artery occlusive disease and their contribution to overall cerebral blood flow volume.

Adult↗
PubMed2005

Bioelectrical impedance analysis: population reference values for phase angle by age and sex.

BACKGROUND: Phase angle is an indicator based on reactance and resistance obtained from bioelectrical impedance analysis (BIA). Although its biological meaning is still not clear, phase angle appears to have an important prognostic role. OBJECTIVE: The aim of this study was to estimate population averages and SDs of phase angle that can be used as reference values. DESIGN: BIA and other methods used to evaluate body composition, including hydrodensitometry and total body water, were completed in 1967 healthy adults aged 18-94 y. Phase angle was calculated directly from body resistance and reactance, and fat mass (FM) was estimated from the combination of weight, hydrodensitometry, and total body water by using the 3-compartment Siri equation. Phase angle values were compared across categories of sex, age, body mass index (BMI), and percentage FM. RESULTS: Phase angle was significantly (P < 0.001) smaller in women than in men and was lower with greater age (P < 0.001). Phase angle increased with an increase in BMI and was significantly inversely associated with percentage fat in men. Phase angle was significantly predicted from sex, age, BMI, and percentage FM in multiple regression models. CONCLUSIONS: Phase angle differs across categories of sex, age, BMI, and percentage fat. These reference values can serve as a basis for phase angle evaluations in the clinical setting.

Adult↗
PubMed1997

Percentile reference values of arterial blood pressure for individuals aged 20 to 60 years from Plovdiv region.

In the course of an epidemiological screening of a Plovdiv region contingent we determined the percentiles of arterial blood pressure of 1458 men and 1146 women (aged 20 to 60 years) selected at random using the SPSS/PC+ program. The derived values for the 75th percentile of the systolic arterial blood pressure for men over 30 years of age and for women aged over 35 years form a group of high-normal systolic arterial blood pressure; for men over 35 years and women over 40 years a first class arterial hypertension is formed at the 75th percentile (USA, 1995). The reference values of the 75th and 90th percentiles of the systolic and diastolic arterial blood pressure rise step-like in men and steeply in women. After 50 years of age the reference values of systolic arterial blood pressure displayed a prevalence in women whereas those of the diastolic arterial blood pressure prevailed in men.

Adult↗
PubMed1984

Reference values of various blood constituents in young minipigs.

In the Göttinger minipig, the reference values of 18 parameters in whole blood or plasma were determined. The results are expressed both as the mean value and +/- 2 SD presuming a symmetrical normal distribution and as the median value with the corresponding range. For most blood constituents, the results of the two modes of calculation were similar. Comparison of the values from young minipigs with those from children shows that these animals are well suited in this respect for experimental work related to human medicine.

Animals↗
PubMed2006

[Reference values for measures of blood flow velocities and impedance indexes in healthy individuals through conventional transcranial Doppler].

OBJECTIVE: To establish reference values for measures of blood flow velocities and impedance indexes in healthy individuals through conventional transcranial Doppler (TCD) and to observe their variations in relation to the age and sex. METHOD: 88 asymptomatic volunteers were examined without antecedents of cardiac, peripheral or cerebrovascular diseases. The TCD were accomplished by the same examiner. The middle, anterior and posterior cerebral arteries were studied through the temporal acoustic window and the vertebral and basilar arteries through the suboccipital acoustic window. The values of mean velocity (MV), peak-systolic velocity (PSV), final diastolic velocity (FDV), resistance index (RI) and pulsatility index (PI) of each examined arterial segment were filed. RESULTS: The reference limits found by us were similar to the described by other authors for all of the studied parameters. There was tendency of the flow velocities decrease and of the impedance indexes increase with moving forward of the age. The values of velocities in the women were superior to the found in men. CONCLUSION: TCD was shown useful in the evaluation of hemodynamic cerebral for our population. Our results are similar to the other studies, so much in the reference values as in relationship with the age and the sex.

Adolescent↗
PubMed1981

Atypicality indices as reference values for laboratory data.

There have been several methods suggested for relating laboratory results to relevant reference values; none has been completely satisfactory. The method described in this paper is referring to atypicality indices for uniform reporting and feasible interpretation of laboratory data. The index associated with a measurement is defined as the probability of finding a results closer to the mean of the reference population than the one actually observed. Thus the larger the index, the less likely the measured value would be in the reference population and the more atypical it becomes. The proposed method, unlike any other, keeps the same simple and desirable features when extended to multivariate situations, that is when several tests are to be interpreted simultaneously.

Creatinine↗
PubMed1981

Reference values for 51Cr-EDTA clearance as a measure of glomerular filtration rate.

Reference values for glomerular filtration rate (GFR) were defined using eight reports including epidemiological studies and studies in kidney donors. Studies using both inulin and 51Cr-EDTA were included. GFR decreased with age, by 4 ml/min decade below the age of 50, and 10 ml/min decade above 50 years of age. No sex difference was found. +/- 2 SD was equal to 25 ml/min at all ages. Based on these findings a nomogram for GFR is presented. Emphasis is given to the use of plasma clearance of 51Cr-EDTA estimated with single injection technique as the new reference method for GFR measurement.

Adolescent↗