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 595 records · Page 33Linked to original sources

PubMed2001

Eosinophil cationic protein (ECP) in school children living in a mountainous area of Norway: a population-based study of ECP as a tool for diagnosing asthma in children with reference values.

BACKGROUND: Most previous studies on eosinophil cationic protein (ECP) have been performed on carefully selected groups of asthmatic patients. Few studies based upon population cohorts have been reported. The primary objective of the present study was to assess the usefulness of serum eosinophil cationic protein (s-ECP) in the diagnosis of asthma in schoolchildren and determine reference values based on measurements in healthy children. METHODS: The population consisted of 216 schoolchildren (aged 7-16 years) who in a previous questionnaire had reported asthma or asthma-like symptoms and a control group. The questionnaire study comprised the entire population of schoolchildren in Upper Hallingdal. After clinical assessment, blood samples, and skin prick tests, these subjects were then reclassified into four groups: atopic and nonatopic asthmatic and nonasthmatics. S-ECP was assessed in relation to atopy, asthma severity, allergen exposure, and sex. RESULTS: The asthma group (n = 105) had significantly higher mean s-ECP level than the nonasthma group (n = 111) (13.3 vs 8.3 microg/l, P < 0.001), with no significant difference between atopic asthmatics and atopic nonasthmatics. Mean s-ECP levels in children with mild, moderate, or severe asthma were 12.1, 18.5, and 12.2 microg/l, respectively. The children with animal dander allergy demonstrated higher levels of s-ECP than children without this allergy (12.9 vs 9.1 microg/l, P = 0.001). The upper reference limit (determined as the 95th percentile in healthy children) of 19.1 microg/l, showed low sensitivity (24%) and high specificity (93%) for the diagnosis of asthma. The positive and negative likelihood ratios for the asthma diagnosis were found to be 3.2 and 0.83, respectively. CONCLUSIONS: The highest s-ECP values were found among children with moderate asthma. Animal dander allergy resulted in elevated s-ECP. However, mean values were still below the reference value of 19.1 microg/l, and the sensitivity was low, suggesting that s-ECP is not a useful parameter for diagnosing asthma in population-based studies.

Adolescent↗

PubMedDate not supplied

Indirect arterial blood pressure measurement in nonsedated Irish wolfhounds: reference values for the breed.

Arterial blood pressure measurements were obtained from 158 healthy Irish wolfhounds using the oscillometric technique to establish reference values for the breed. In contrast to other sight hounds, Irish wolfhounds have low arterial blood pressure. Mean systolic pressure for the group was 116.0 mm Hg. Mean diastolic pressure was 69.2 mm Hg, and the mean value for mean arterial pressure was 87.8 mm Hg. Blood pressure measurements were higher in older wolfhounds than in young dogs. There was no difference between systolic and mean arterial blood pressures in lateral recumbency compared to standing position. However, diastolic pressure was slightly lower when standing. Calm dogs had lower pressure than anxious wolfhounds. There was a significant interaction between the effects of age, gender, and mood on systolic, diastolic, and mean arterial blood pressure values.

Animals↗

PubMed1994

Trace element reference values in tissues from inhabitants of the European Union. VIII. Thallium in the Italian population.

In order to establish reference values of thallium in tissues of the general population the element was determined in blood (TlB) and urine (TlU) of 123 healthy inhabitants living in the Marche region, Central Italy. The analysis was carried out by inductively coupled plasma-mass spectrometry (ICP-MS; detection limit in our experimental conditions, 0.001 micrograms Tl/I), which was validated by neutron activation analysis (NAA) and laser induced fluorecence (LIF) spectroscopy. The check of pre-analytical factors indicated a low risk of contamination and loss of Tl during sampling, handling and storage before the instrumental analysis (blank of the entire procedure less than the detection limit). Mean values of TlU and TlB were 0.066 micrograms Tl/l and 0.063 micrograms Tl/l, respectively (median in both cases 0.057 microgram Tl/l). No conclusive evidence concerning the distribution followed by our data set, normal or log-normal, were drawn, although Lilliefors test and Kolmogorov's D-test showed a tendency for TlB to follow both the normal and the log-normal while TlU followed a log-normal distribution. Overall correlations between TlU and TlB are rather weak. A significant, but not high, correlation (P < 0.0004, r = 0.44) was observed in females. Age, sex, smoking habits and alcohol consumption did not seem to play any role on TlU and TlB. Tentatively proposed reference intervals are 0.019-0.17 microgram Tl/l (urine) and 0.014-0.19 microgram Tl/l (blood).

Adult↗

PubMed2001

Reference values for echocardiographic measurements in urban and rural populations of differing ethnicity: the Strong Heart Study.

Discrepancies in reported reference values for left ventricular (LV) dimensions and mass may be due to imaging errors with early echocardiographic methods or effects of subject characteristics and inclusion criteria. To determine whether contemporary echocardiographic methods provide stable normal limits for left ventricular measurements in different populations, M-mode/2-dimensional echocardiography was applied in 176 American Indian participants in the Strong Heart Study and 237 New York City residents who were clinically normal. No consistent difference in any measure of LV size or function existed between populations. Upper normal limits (98th percentile) for LV mass were 96 g/m(2) in women and 116 g/m(2) in men and 3.27 cm/m for LV chamber diameter normalized for height. Thus contemporary M-mode/2D echocardiography provides reference ranges for LV measurements that approximate necropsy measurements and have acceptable stability in apparently normal white, African-American/Caribbean, and American Indian populations.

Aged↗

PubMed1999

Reference values for the midluteal plasma progesterone concentration: evidence from human menopausal gonadotropin-stimulated pregnancy cycles.

OBJECTIVE: To determine reference values for the midluteal plasma progesterone concentration. DESIGN: Retrospective analysis. SETTING: Infertility clinic at an academic medical center. PATIENT(S): One hundred ninety-two infertile women who became pregnant after induction of ovulation with hMG. INTERVENTION(S): The plasma progesterone level was measured during the midluteal phase of the hMG treatment cycle. MAIN OUTCOME MEASURE(S): The midluteal plasma progesterone concentration was correlated with the outcome of the pregnancy. RESULT(S): In this cohort of 192 women in whom ovulation was induced with hMG and 5,000 IU of hCG, the mean midluteal plasma progesterone concentrations were 29.07 ng/mL, 25.85 ng/mL, 31.49 ng/mL, 41.39 ng/mL, and 28.64 ng/mL in all cycles that resulted in pregnancy, cycles that resulted in full-term singleton pregnancy, cycles that resulted in full-term multiple pregnancy, cycles that resulted in preterm pregnancy, and cycles that ended in miscarriage, respectively. There was no statistically significant difference in the progesterone concentration between the cycles that resulted in full-term pregnancy and those that ended in miscarriage, but there was a statistically significant difference between the cycles that resulted in singleton pregnancy and those that resulted in multiple pregnancy. The minimum value that was compatible with a full-term pregnancy in this cohort of women was 10.83 ng/mL. CONCLUSION(S): In a cohort of 192 women, the minimum plasma progesterone concentration on day 7 in women who attained a full-term pregnancy after induction of ovulation with 5,000 IU of hCG was 10.83 ng/mL.

Abortion, Spontaneous↗

PubMed1981

Relative reference values for clinical chemical and haematological quantities in 'healthy' elderly people.

A search of the literature revealed a paucity of data on reference values for clinical chemical and haematological quantities in reasonably 'healthy' ambulant persons above 65 years of age. On the basis of 90 papers, concerning 37 different types of quantities, the median values for men and for women at 30, 50, 65, and 80 years are calculated relative to the value in men at 30 years. This transformation reduces influences of analytical and demographic factors that have caused considerable systematic differences in the original data. The reference distribution is described as regards symmetry and the change in dispersion with age. The results are given in a table and show four types of changes with age: no significant variation, a fall, an increase or a maximum somewhere between 30 and 80 years; the type of change often depends on sex.

Adult↗

PubMed1989

Reference values for trabecular and cortical vertebral bone density in single and dual-energy quantitative computed tomography.

The validity of reference values for vertebral bone mineral density (BMD) reported in the literature has frequently been questioned. The introduction of dual-energy methods, new calibration systems, and automated image evaluation algorithms, has also made it necessary for us to re-evaluate BMD values in a normal population. We present patient selection criteria, CT measurement and evaluation protocols and results of single energy (SEQCT) and dual energy quantitative CT (DEQCT) for trabecular (tBMD) and cortical (cBMD) bone density in 135 males and 139 females. For SEQCT, tBMD loss rates of 1.7 and 1.8 mg/ml per year for males and females, respectively, were determined by linear regression. The respective DEQCT data show smaller decrements with age. Different statistical models for tBMD in females were tested; models based on a multiphase variation of tBMD yielded an improvement of the fit. For cBMD the percent rate of loss with age is much smaller than for tBMD; females showed a significantly higher loss rate than males, however. A comparison of our results with published data is included.

Absorptiometry, Photon↗

PubMed2006

[Reference values for the vestibulo-ocular reflex response to the head shaking and the bithermal caloric tests].

OBJECTIVE: To obtain reference values for the vestibulo-ocular reflex response to the head-shaking nystagmus and the bithermal caloric test in the spanish population. PATIENTS AND METHODS DESIGN: A descriptive study. SET UP: General hospital. INDIVIDUALS: One hundred and seven healthy sex and age stratified voluntiers were included. The final sample included 97 individuals over 18 years of age. INTERVENTION: Spontaneous nystagmus (SN), head-shaking nystagmus (HSN) and caloric induced nystagmus were explored. The eyes movement was recorded by a video-oculographic system. The SN or HSN was considered significant when at least 6 consecutive beats with a slow phase velocity of 2 degrees/sec were detected. The caloric test was performed with water flow at 250mL/20 s at 30 degrees C and 44 degrees C with an interval of 10 minutes between irrigations. The percentage of canal paresis (CP) and directional preponderance (DP) was calculated using maximum slow phase velocity and the Jongkees index formula. MAIN OUTCOME MEASUREMENTS: Presence of SN, horizontal and vertical SHN, percentage of CP and DP. RESULTS: SN was found in 10,3% individuals (6 women and 4 men). Horizontal HSN was also observed in 9 women and 10 men (19,5%), and vertical HSN in 8 women and 10 men (18,6%). The mean and 95 percentil for CP were 13,10 and 28,60 in women and 11,02 and 27,30 in men. For DP, the mean and 95 percentil were 11,76 and 35,80 in women and 11,58 and 28,65 in men. The 5 percentils for slow phase velocity of nystagmus after each irrigation were 6,30; 5,14; 5,96; 4,02 degrees/s (left ear 44 degrees, right ear 44 degrees, left ear 30 degrees, right ear 30 degrees, respectively) in the group of women; and 5,82; 6,99; 5,67; 4,55 degrees/s in men (with the same irrigation sequence). CONCLUSION: Results presented should be considered as a population-based norms and may be useful as references for water bithermal test for VOG studies. The SN or HSN could be observed in subjects without vestibular pathology.

Adolescent↗

PubMed1991

Reference values for the ambulatory blood pressure and the blood pressure measured at home: a population study.

In order to determine reference values for the ambulatory blood pressure, a population sample of 328 subjects, aged 20-81 years, who reported themselves to be in good health, was investigated. The ambulatory blood pressure was recorded over 24 h, taking measurements at 20 min intervals from 8 am to 10 pm, and at 45 min intervals from 10 pm to 8 am. Blood pressure was also measured by trained observers on each of two separate home visits (5 readings per visit). The ambulatory blood pressure in the 328 subjects averaged 118/71 mmHg over 24 h, 124/76 mmHg during the day (10 am-8 pm), and 108/62 mmHg at night (0 am-6 am). Blood pressure measured by an observer at the occasion of the second home visit was 4/5 mmHg lower (P less than 0.001) than the daytime ambulatory blood pressure. The 95th centiles for the daytime ambulatory pressures were 144/95 mmHg in 85 men below age 50; 154/90 mmHg in 74 men aged greater than or equal to 50 years; 132/85 mmHg in 96 women below age 50; and 151/91 mmHg in 73 women aged greater than or equal to 50 years. The 95th centiles for the nighttime pressures in these four sex-age groups were 124/79, 140/83, 121/70, and 132/72 mmHg, respectively.

Adult↗

PubMed1997

Population-based reference values for IGF-I and IGF-binding protein-1: relations with metabolic and anthropometric variables.

Population-based reference values for IGF-I and IGF-binding protein-1 (IGFBP-1) have been established. One hundred and one women and the same number of men, 20-70 years old, were randomly selected from the population registry in the community of Linköping. Participation rate was 67%. Venous blood was drawn in the fasting state. Serum IGF-I was measured by RIA after acid-ethanol extraction and IGFBP-1 was determined by ELISA. IGF-I levels did not differ between genders and the decline with age was similar in men and women (men: Y = 366-3.28 x age (years), r = -0.61, P < 0.0001; women: Y = 386-3.49 x age, r = -0.57, P < 0.0001, P = 0.4 for difference in slope). There were negative correlations between IGF-I and plasma lipids and blood pressure in both genders, but none was independent of age. Serum angiotensin-converting enzyme activity correlated positively with IGF-I in men independently from age (r = 0.21, P = 0.01). The distribution of IGFBP-1 was positively skewed and it was higher in women than in men (5.9 +/- 4.8 micrograms/l and 4.0 +/- 3.3 micrograms/l respectively; Mann-Whitney, P = 0.002). In men and in the women not taking oestrogen, IGFBP-1 correlated positively with age (Spearman rank correlation (Spearman: men: r = 0.32, P = 0.002; women: r = 0.24, P = 0.03). C-peptide correlated negatively (Spearman: men: r = -0.38, P = 0.002; women: r = -0.49, P < 0.000) and sex hormone binding globulin positively with IGFBP-1 (Spearman: men: r = 0.50, P < 0.0001; women: r = 0.55, P < 0.0001). IGF-I declined with age while IGFBP-1, which is considered to modulate the free bioactive fraction of IGF-I, increased. This suggests that IGF-I activity might be even lower in elderly subjects than is accounted for by the low total IGF-I.

Adult↗

PubMed2002

Objective criteria for partitioning Gaussian-distributed reference values into subgroups.

BACKGROUND: The aim of this study was to develop new and useful criteria for partitioning reference values into subgroups applicable to gaussian distributions and to distributions that can be transformed to gaussian distributions. METHODS: The proposed criteria relate to percentages of the subgroups outside each of the reference limits of the combined distribution. Critical values suggested as partitioning criteria for these percentages were derived from analytical bias quality specifications for using common reference intervals throughout a geographic area. As alternative partitioning criteria to the actual percentages, these were transformed mathematically to critical distances between the reference limits of the subgroup distributions, to be applied to each pair of reference limits, the upper and the lower, at a time. The new criteria were tested using data on various plasma proteins collected from approximately 500 reference individuals, and the outcomes were compared with those given by the currently widely applied and recommended partitioning model of Harris and Boyd, the "Harris-Boyd model". RESULTS: We suggest 4.1% as the critical minimum percentage outside that would justify partitioning into subgroups, and 3.2% as the critical maximum percentage outside that would justify combining them. Percentages between these two values should be classified as marginal, implying that nonstatistical considerations are required to make the final decision on partitioning. The correlation between the critical percentages and the critical distances was mathematically precise in the new model, whereas this correlation is rather approximate in the Harris-Boyd model because focus on the difference between means in this model makes high precision hard to achieve. The application examples suggested that the new model is more radical than the Harris-Boyd model. CONCLUSIONS: New percentage and distance criteria, to be used for partitioning gaussian-distributed data, have been developed. The distance criteria, applied separately to both reference limit pairs of the subgroup distributions, seemed more reliable and correlated more accurately with the critical percentages than the distance criteria of the Harris-Boyd model. As opposed to the Harris-Boyd model, the new model is easily adjustable to new critical values of the percentages, should they need to be changed in the future.

Clinical Laboratory Techniques↗

PubMed1982

[alpha 1-antitrypsin: reference values in serum and plasma with benzoyl-D,L-arginine-p-nitroanilide, a chromogenic substrate].

Reference values for alpha 1-antitrypsin were determined using a commercially available kit for continuous assay at 25 degrees C. With a population of 100 probands aged between 20 and 60 years, a reference range of 1.4-2.4 kIU/l (1.9-3.4 g/l) was obtained for serum, and 1.4-2.1 kIU/l (1.9-3.0 g/l) for plasma. In each case, these ranges correspond to the 5th to 95th percentile. No variations according to age or sex were observed, or was any difference noted between preprandial and postprandial activities, or between values in smokers and nonsmokers. Significantly different values were found in the group of women taking oral steroid contraceptives and the group not taking such contraceptives. If the dilution of the blood sample with citrate solution is taken into account in calculating the activity in citrated plasma, it is apparent that higher values are found in plasma than in serum (median 13%): Hence, the in vivo-alpha 1-antitrypsin activity can most probably be better determined using a plasma sample.

Adult↗

PubMed1995

Reference values of arterial oxygen tension in the middle-aged and elderly.

The lack of available reference values of arterial PO2, particularly for elderly persons, led us to study a sample of 194 normal nonsmoking subjects, equally distributed over all age ranges from 40 to 90 yr. The radial artery was punctured and blood samples were taken and analyzed on an automated, computerized gas-analyzer. The trend of the mean values of PaO2 in the 5-yr class intervals of age showed a clear decline up to the 70- to 74-yr class, and then an inversion. The two regression lines intersecting at this point provided a better fit to the data than did a single regression line (R22 - R12 = 0.918 - 0.678 = 0.24; F = 20.49, p = 0.0027). The relationship of PaO2 with age was thus subsequently considered for the two subgroups (40 to 74 yr; > or = 75 yr) identified on the basis of this cutoff. Because of the significant influence on Pao2 of age, body-mass index (BMI), and PaCO2 in the group 40 to 74 yr of age, the following reference equation was constructed: Pao2 (mm Hg) = 143.6 - (0.39 . age) - (0.56 . BMI) - (0.57 . PaCO2); R2 = 0.28; SEE = 7.48; p < 0.0001. For subjects > or = 75 yr old, for whom there was no correlation with age, BMI, or PaCO2, only the mean +/- SD and 5th percentile of PaO2 were reported (83.4 +/- 9.15 mm Hg and 68.4 mm Hg, respectively). PaCO2 values were not correlated with either age or BMI; the mean +/- SD was 35.79 +/- 3.87 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Pulse oximetry reference values at high altitude.

Pulse oximetry is becoming popular for measuring oxygen saturation of haemoglobin in paediatric patients. There are no reference values for children living at high altitudes, and the aim of this study was to determine the values of oxygen saturation of haemoglobin in healthy children in Bogota (2640 m above sea level). The saturation was determined in 189 children aged 5 days to 24 months with a Nellcor N10 oximeter. Mean values and 95% confidence intervals (CI) were calculated. Analysis of variance was used for assessing the differences in saturation with age and physiological status. The values were normally distributed with a mean (SD) of 93.3 (2.05)% and 95% CI of 93.0% to 93.6%. There were no clinically important differences in the oxygen saturation of haemoglobin in the range of ages included. The mean saturation in sleeping children was significantly lower than that during other physiological states (91.1% v 93.3%) but the difference was not clinically important. As expected, the values for the oxygen saturation of haemoglobin in the children studied were lower than those reported from children living at sea level. These estimates can be used for interpreting results of the oxygen saturation in haemoglobin in children from Bogota and other cities located at a similar altitude.

Altitude↗

PubMed1988

Reference values of blood parameters in beef cattle of different ages and stages of lactation.

Reference (normal) values for 12 blood serum components were determined for 48 Shorthorn cows (2-10 years old) and their 48 calves, 357 crossbred cows (12-14 years old), 36 feedlot bulls and 36 feedlot steers. In addition, hemoglobin, hematocrit, triiodothyronine, thyroxine and cortisol levels were determined for the crossbred cows, and feedlot bulls and steers. Reference values were tabulated according to sex, age and stage of lactation. Serum concentrations of urea, total protein and bilirubin, and serum activity of aspartate aminotransferase and lactate dehydrogenase increased with age (P less than 0.05), while calcium, phosphorus and alkaline phosphatase decreased with age (P less than 0.05) from birth to the age of ten years. The Shorthorn cows had the highest levels of glucose at parturition (P less than 0.05) with decreasing levels during lactation. Creatinine concentration decreased during lactation and increased during postweaning. Both lactate dehydrogenase and aspartate aminotransferase levels increased (P less than 0.05) during lactation. Urea and uric acid were present at higher concentrations in lactating than nonlactating cows (P less than 0.05). The values reported, based on a wide age range and large number of cattle, could serve as clinical guides and a basis for further research.

Alkaline Phosphatase↗

PubMedDate not supplied

[Erythrocyte reference values in a Coulter S-Plus STKR, in healthy adults living at 2,240 meters above sea level].

To determine reference values of red blood cell counts in a Coulter S-Plus STKR, we studied 122 males and 147 females selected from the hospital staff (physicians, chemists, nurses) and blood donors. Their ages ranged from 17 to 45 years. Iron and total iron binding capacity in serum, and Zn-protoporphyrin and folates in erythrocytes were measured to include only normal subjects without nutritional deficiencies. Two males (1.6%) and 21 females (14.3%) were excluded due to iron deficiency, and one man (0.7%) and one woman (0.8%) to folate deficiency. All red cell parameters, except the mean cell volume, showed a gaussian distribution (Lilliefors test). Their mean +/- standard deviation were: [formula: see text].

Adolescent↗

PubMed2002

Distribution of 24-h ambulatory blood pressure in children: normalized reference values and role of body dimensions.

BACKGROUND: Twenty-four-hour ambulatory blood pressure monitoring (ABPM) is an essential tool in the diagnosis and therapeutic monitoring of arterial hypertension in children. The statistical use of pediatric ABPM reference values has been compromised by the non-Gaussian distribution of 24-h blood pressure (BP) in children. OBJECTIVE: To develop distribution-adjusted pediatric ABPM reference tables. METHODS: From cross-sectional ABPM data obtained in 949 healthy children and adolescents aged 5-20 years, a set of reference tables was developed for 24-h, daytime and night-time mean values of systolic, diastolic, mean arterial BP and heart rate, utilizing the LMS method to account for the variably skewed distribution of ABPM data. Age- and gender-specific estimates of the distribution median (M), coefficient of variation (S) and degree of skewness (L) were obtained by a maximum-likelihood curve-fitting technique. The estimates of, and can be used to normalize ABPM data to gender and age or height. RESULTS: Re-application of the established, and values in the reference population confirmed appropriate normalization of ABPM values. Height standard deviation scores (SDS), body mass index (BMI) SDS and heart rate SDS were independent positive predictors of 24-h systolic BP SDS. Diastolic 24-h mean BP SDS showed a weak correlation with BMI SDS only. CONCLUSIONS: The use of LMS reference tables permits calculation of appropriate SDS values for ABPM in children. Whereas systolic 24-h BP is independently correlated with age, relative height and obesity, diastolic values are almost independent of age and relative height, and weakly associated with relative obesity.

Adolescent↗

PubMed1977

[Study of the reference values and nyctohemeral cycle of serum iron].

Marked variations in the same individual of serum iron levels may be due to a circadian rhythm. We determined the reference values of serum iron in a population of blood donors who had no blood disease. The very wide reference interval found (0.47 to 1.75 mg/l in man and 0.36 to 1.66 mg/l in women) was due to physiological variations rather than analytical variations. We also demonstrated in individuals with a normal life rhythm, a circadian rhythm for iron with maximal levels in the morning (8 to 12) and minimal levels in the evening (8 p.m. to midnight) the ratio of these levels is usually between 1.5 and 2, but may reach much higher figures. On the other hand, the total fixation capacity varies little over 24 hours. In night workers, one may note a displacement of the cycle with a maximum towards 8 p.m. a minimum at 8 a.m. In diabetics, the circadian rhythm exists but with a lower amplitued than in healthy subjects. In a few cases a hemochromatosis, one may note disappearance of the cycle.

Adult↗