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PubMedDate not supplied

Reference values for erythrocyte sedimentation rate of middlescent people as a function of altitude.

The purpose of this paper is to provide a scientific basic for a unified standard for the reference value of middlescent people's erythrocyte sedimentation rate (ESR) in China. ESR measurements for healthy middlescent people were collected according to the Wintrobe method and the relationship between the reference value of middlescent people's ESR and altitude was tested in this paper It was found that the reference value of middlescent people's ESR decreases when the altitude gradually increases, and the relationship is quite significant. Univariate regression analysis was used to deduce two regression equations: Y1 = 13.14-0.00245X +/- 2.98 (males) and: Y2 = 22.00-0.00397X +/- 4.85 (females). If the altitude value of a particular area of China is known, the reference value of middlescent people's ESR can be calculated by means of these regression equations. Furthermore, depending on the altitude, China can be divided into three biogeographic districts: Qingzang District, Central District, and Eastern District.

Adult↗

PubMed1998

Pediatric reference values for respiratory resistance measured by forced oscillation.

OBJECTIVES: To determine, in North American children, reference values for respiratory resistance measurements by the forced oscillation (Rfo) technique and to examine whether sitting height, as index of truncal length, is a better determinant of resistance, less influenced by race and gender, than standing height. DESIGN/SETTING: A prospective cross-sectional study of healthy nonobese children, carefully selected for absence of atopy, exposure to tobacco smoke, and recent upper respiratory tract infection. MEASUREMENTS: Three measurements of respiratory resistance by forced oscillation were obtained at the fixed frequencies of 8 Hz (Rfo8), 12 Hz (Rfo12), and at 16 Hz (Rfo16) using the Custo Vit R (Custo Med GMBH; Munich, Germany). In cooperative children, routine spirometry (FEV1, FVC, and peak expiratory flow rate [PEFR]) was also performed. RESULTS: We recruited 217 healthy children aged 3 to 17 years. Reproducible measurements of Rfo8 were obtained for 206 children, Rfo12 for 197 children, and Rfo16 for 209 children. Normal FEV1, FVC, and PEFR values were documented in all 69 subjects who were able to reproducibly cooperate with spirometry. Multiple linear regression identified measurements of either sitting or standing height as the best, and equally strong, determinants of respiratory resistance at all three frequencies. Gender and race were not important factors once either sitting or standing height measurement was considered. Our regression equations at 8 Hz are comparable to published reference values obtained at fixed frequencies of 6, 8, and 10 Hz using other instruments. However, in comparison to our results, prior values tended to underestimate resistance in the shortest children or to overestimate it in the tallest ones. Our regression equation for Rfo12 is similar to the only previously published one, while no reference values at 16 Hz were available for comparison. CONCLUSIONS: Height is the best predictor for total respiratory resistance at 8, 12, and 16 Hz in children aged > or = 3 years. Use of sitting height does not appear to be a stronger determinant of resistance than standing height.

Adolescent↗

PubMed1984

Clinical biochemical and hematologic values of the American Miniature Horse: reference values.

Sixteen clinical biochemical determinations and 13 hematologic measurements were performed on 49 healthy American Miniature Horses of mixed age and both sexes. Serum triiodothyronine and thyroxine values were also determined. Serum biochemical test results from American Miniature Horses compared favorably with values for full-sized horses, whereas differences in hematologic test results were noticed between American Miniature Horses and full-sized horses.

Animals↗

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↗

PubMed2001

Tau and Abeta42 in cerebrospinal fluid from healthy adults 21-93 years of age: establishment of reference values.

BACKGROUND: Tau protein and the 42-amino acid form of beta-amyloid (Abeta42) measured in cerebrospinal fluid (CSF) have been proposed as potential biochemical diagnostic markers for Alzheimer disease. For the introduction of these assays in clinical practice, adequate reference values are of importance. METHODS: CSF samples were obtained from 231 neurologically and psychiatrically healthy individuals, 21-93 years of age, all with a MiniMental State examination score of 28 or above. Standardized ELISAs were used to measure tau and Abeta42 in CSF. Following IFCC recommendations, we used a rank-based method; the 0.90 and 0.10 fractiles were estimated to establish reference values for CSF-tau and CSF-Abeta42, respectively. Putative confounding factors, such as the influence of the passage of proteins from peripheral blood to CSF, influence of dysfunction of the blood-brain barrier, and freezing and thawing of CSF, were investigated. RESULTS: A correlation with age was found for CSF-tau (r = 0.60; P <0.001). Therefore, separate reference values for different age groups were established for CSF-tau: <300 ng/L in the group 21-50 years of age, <450 ng/L in the group 51-70 years of age, and <500 ng/L in the group 71-93 years of age. CSF-Abeta42 did not correlate with age (r = -0.045), and the reference value was set to >500 ng/L. No correlation was found between blood-brain barrier function and CSF-tau or CSF-Abeta42. CONCLUSIONS: These reference values can be applied when using CSF-tau and CSF-Abeta42 in clinical practice.

Adult↗

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↗

PubMed2006

Serum biochemical reference values for gestating and lactating sows.

Reference values have been established for serum biochemical parameters in sows from high producing pig herds. In total, 132 clinically healthy sows from eight breeding herds were serially sampled three weeks and one week before farrowing, and at one week and three weeks after farrowing. Fourteen serum biochemical parameters, focusing mainly on energy and protein metabolism, hepatobiliary and kidney function and inflammation, were investigated. The reproductive state significantly influenced the investigated parameters, other than for urea and non-esterified fatty acids. First parity sows showed higher concentrations of gamma-glutamyltransferase, phosphorus and haptoglobin, and higher albumin/globulin and haptoglobin/albumin ratios compared to sows with 2 parities. The concentrations of creatinine, globulin and total protein however were lower in first parity sows. Between-herd variations were especially high (>50%) for gamma-glutamyltransferase, alkaline phosphatase and non-esterified fatty acids. Serum biochemical parameters constitute an important diagnostic tool to assess the health status of sows, but to interpret the outcome properly, it is important to consider reproductive state and parity.

Animals↗

PubMed1993

Quantitative organic acid analysis in cerebrospinal fluid and plasma: reference values in a pediatric population.

Quantitative reference values for the concentrations of organic acids in cerebrospinal fluid (CSF) and plasma, as well as ratios of individual organic acids between CSF and plasma, were determined in twenty-three pairs of samples from pediatric patients. Twenty-six organic acids were present and quantifiable in all or the majority of plasma and CSF specimens (limit of detection 1 mumol/l). There were substantial differences between subgroups of organic acids, best reflected by the ratios of individual acids between CSF and plasma. Metabolites related to fatty acid oxidation were present in CSF in substantially lower amounts than in plasma. Organic acids related to carbohydrate and energy metabolism and to amino acid degradation were present in CSF in equal or slightly lower amounts than in plasma. Finally, some organic acids were found in substantially higher amounts in CSF than in plasma, e.g. glycolate, glycerate, 2,4-dihydroxybutyrate, citrate and isocitrate. Quantitation of organic acids in CSF and plasma should aid diagnosis and monitoring of treatment of patients with organic acid disorders.

Acids↗

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↗

PubMedDate not supplied

Acute health reference values: overview, perspective, and current forecast of needs.

A number of organizations have developed acute inhalation health reference values, each with (1) a specific purpose, (2) populations to protect, (3) exposure scenarios (accidental releases, workplace, routine excursions of ambient levels), and (4) severity of adverse health effects considered in their development. The first section of this article reviews the existing values from different organizations and describes their purposes and method of development. The second part of the article provides a comparative review of how the values were derived, the critical endpoints considered for each value, the populations being protected by each value, and the potential for use outside of their intended purpose (e.g., Homeland Security, regulatory analysis, etc.). Additionally, an analysis of the acute inhalation reference values that was developed in support of the Office of Air and Radiation's residual risk assessment for hazardous air pollutants is presented and reviewed. The third and final part of the article focuses on the efforts of the U.S. Environmental Protection Agency (EPA) to develop a set of less-than-lifetime reference values, along with a discussion of how that effort fits with the existing sets of values described in the prior sections.

Air Pollutants↗

PubMedDate not supplied

Cross-sectional reference values for height, weight and body mass index of school children living in Tehran, Iran.

AIM: The aim of the study was to create reference values for weight, height and body mass index (BMI) of school children living in Tehran. METHOD AND SAMPLES: The study subjects consisted of 1,420 girls between 6 and 17 years of age and 1,515 boys between 6 and 15 years of age. Samples were collected by a multistage sampling method from schools in different areas of Tehran. All participants were established to be healthy and their height, weight and BMI evaluated. Reference standard values estimated by the LMS method using LMS Light software and 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 97th and 85th (only for BMI) centiles were constructed and the results compared with US reference values. RESULTS: The centiles provided a good fit to the data. In boys, there were some significant differences of mean standard deviation scores (SDS) of height and BMI from zero, but there were no significant differences in weight. In girls, the mean SDS of height, weight and BMI were significantly lower than zero, especially for 7-9 years of age. Among 12-13-year-old girls, the mean SDS of height, weight and BMI came closer to zero, and the differences were not significant. Thereafter, although girls seemed to be shorter than US reference measures, their weight and BMI did not differ from reference values significantly. CONCLUSION: Our results for boys between 6 and 15 years are comparable with US reference values; however, the US reference values, especially for height, are not applicable for Iranian girls between 6 and 17 years.

Adolescent↗

PubMed2003

Reference values and predictors of white blood cell subset counts: a cross-sectional study among HIV seronegative pregnant women in Zimbabwe.

OBJECTIVE: To identify predictors and develop reference values of white blood cell subset counts for pregnant black women in Zimbabwe. STUDY DESIGN: In this cross-sectional study, multiple linear regression (MLR) analysis was employed to assess the relationship of WBC subset counts with age, gestational age, gravidity, season, serum retinol, beta-carotene, ferritin, folate and alpha-1 antichymotrypsin among 998 women 22-35 weeks pregnant attending antenatal care (ANC) in Harare, Zimbabwe. RESULTS: Mean age was 24.0 (95% CI; 23.6-24.4), range 14-45 years. The mean gestational age was 29.2 (95% CI; 29.0-29.4), range 22-35 weeks. Median gravidity was 2, range 1-9. Predictors of neutrophil counts were gestational age, season and serum ferritin, the latter in interaction with gravidity (interaction, p = 0.016). Mean lymphocyte count was 0.13 x 10(9)cells/l higher in gravida >4 than gravida 1-3, and 0.35 x 10(9)cells/l higher in the late rainy than other seasons. Predictors of monocyte counts were gestational age, serum folate and season, while eosinophil counts declined with advancing gestation. Reference values adjusted or unadjusted for identified predictors were different from those of pregnant and non-pregnant white women reported in the literature. CONCLUSIONS: Gravidity, season and micronutrient status influence WBC counts during pregnancy and therefore are of physiological and clinical importance. WBC reference values in the literature were not applicable obviating the need for local reference values.

Adolescent↗

PubMed2003

[Reference values for erythrocyte cholinesterase activity in the working population of Antioquia, Colombia, according to the Michel and EQM techniques].

OBJECTIVE: To establish reference values for erythrocyte cholinesterase (EC 3.1.1.7) activity for the active working population of two regions of the department of Antioquia, Colombia, that are located at different altitudes above sea level. METHODS: We took representative samples from populations of active working persons 18 to 59 years old from two regions in the department of Antioquia: (1) the Aburrá Valley (1 540 m above sea level) and (2) the near east of the department (2 150 m above sea level). We excluded workers who were using cholinesterase-inhibiting substances in their work or at home, those who had a disease that altered their cholinesterase levels, and those who said they were not in good health. We measured the erythrocyte cholinesterase activity using two methods: (1) the Michel method and (2) the EQM method (EQM Research, Cincinnati, Ohio, United States of America). We carried out the measurements with 827 people, 415 from the Aburrá Valley and 412 from the near east region. We compared proportions using the chi-square test and Fisher's exact test. We utilized the Student's t test for independent samples to compare two averages. To simultaneously compare three or more averages, analysis of variance was used, followed by the Newman-Keuls multiple-range test. When the variables were not normally distributed or when the variances were not homogeneous, Kruskal-Wallis nonparametric analysis of variance was used to compare the medians. Three computer software programs were used in the statistical analysis: SPSS 9.0, SGPlus 7.1, and Epi Info 6.04. In all the statistical tests the level of significance was set at P < 0.05. RESULTS: The average erythrocyte cholinesterase activity value that we found for the studied population by using the Michel method was 0.857 delta pH/hour (95% confidence interval (CI): 0.849 to 0.866), and the average value found through the EQM method was 35.21 U/g hemoglobin (95% CI: 34.82 to 35.60). With the Michel method: (1) the enzymatic activity differed significantly between the two regions, according to the Newman-Keuls test; (2) within each region, the enzymatic activity was significantly higher among males than among females, according to the Newman-Keuls test; and (3) in none of the region-sex strata was there a statistically significant influence of age on the enzymatic activity. Using the EQM method, there were no statistically significant differences by region, sex, or age group. CONCLUSIONS: The erythrocyte cholinesterase activity values found by the two analytical techniques were significantly higher than the values from outside Colombia that are now being used as reference values in the country, which poses both clinical and epidemiological problems. We recommend that the data from this study be adopted as the reference values in Colombia.

Adolescent↗

PubMed2005

Holotranscobalamin and total transcobalamin in human plasma: determination, determinants, and reference values in healthy adults.

BACKGROUND: We developed microbiological assays (MBAs) to identify determinants and to establish reference values for cobalamin bound to transcobalamin [holotranscobalamin (holoTC)] and total TC in plasma. METHODS: We captured holoTC with magnetic beads with TC antibodies and used a conventional MBA for cobalamin measurements. Total TC was determined as holoTC after TC was saturated with cyanocobalamin. The new assays were compared with published methods. Determinants and reference values were determined in 500 blood donors, ages 18-69 years. RESULTS: Determination of cobalamin, holoTC, and TC by MBA required <150 microL. HoloTC and TC by MBA correlated with holoTC by RIA (r = 0.95) and TC by ELISA (r = 0.79), respectively. Between-day CVs for holoTC and total TC were 4%-9%. Women had lower holoTC than men, but only at age < or = 45 years. In multivariate regression analyses, holoTC was positively associated with age (in women only), creatinine (in men only), and plasma concentrations of total TC, folate, and cysteine, but inversely correlated with homocysteine and methylmalonic acid. For all study participants, total TC was associated with holoTC and number of TCN2 766C alleles; in female participants only, total TC was also associated with age, homocysteine, and cysteine. Reference values were 670-1270 pmol/L for TC and 42-157 pmol/L for holoTC, but they differed according to age and sex. CONCLUSIONS: Our MBAs for TC and holoTC required low plasma volume and performed acceptably compared with other methods. Determinants of holoTC and TC differed between men and women and according to age. Separate reference intervals for holoTC should be considered in younger women.

Adolescent↗

PubMed1999

The impact of gender, puberty and body mass on reference values for urinary growth hormone (GH) excretion in normally growing non-obese and obese children.

OBJECTIVE: There is a lack of normal reference data on urinary GH (u-GH) excretion in children. We have investigated the impact of age, gender, pubertal development and body mass on reference values for u-GH excretion in normally growing non-obese and obese children. STUDY DESIGN: u-GH levels were evaluated in 1153 healthy normal children (aged 5-14) and in 684 obese children (body mass index, BMI: > 75th). u-GH levels (ng/8 h) were determined by ELISA as the mean value of three consecutive first morning voidings. RESULTS: Reference values (5-95th centile) for u-GH excretion in obese and non-obese children of both sexes are reported. In normal prepubertal children median u-GH levels were relatively stable and superimposable in the two sexes; subsequently, u-GH levels increased, reaching a peak value at 13 years in both sexes. Significant increments (P < 0.0001) in u-GH levels were shown at B2 for females and at G3 for males. A slight decline was evident at 14 years. In obese children, median u-GH concentrations were significantly lower than those recorded in normal children of prepubertal age and at all stages of puberty (except in females at B2), in spite of their comparable normal height. u-GH levels significantly increased at puberty also in obese children, although the pubertal rise was significantly (P < 0.001) lower (1.7-fold in both sexes) than that observed in normal children (2.5-fold in boys and 2.3-fold in girls). A multiple regression analysis showed that both chronological age (beta: 0.20), BMI (beta: - 0.11), gender (beta: - 0.04) and pubertal stage (beta: 0.25) contributed significantly to the physiological variation in u-GH levels (multiple R: 0.44, P < 0.00001). CONCLUSIONS: This study provides reference values for u-GH in normally growing non-obese and obese children, analysing the impact of gender, puberty and body mass on this parameter. In agreement with previous studies, which demonstrate blunted GH-responses to provocative stimuli and reduced nocturnal GH concentration, obese children have significantly lower u-GH levels than age-matched normal weight children, both before and during puberty.

Adolescent↗

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↗

PubMed2005

Avian toxicity reference values for perfluorooctane sulfonate.

Toxicity reference values (TRVs) and predicted no effect concentrations (PNECs) were derived for perfluorooctane sulfonate (PFOS) based on the characteristics of a top avian predator. On the basis of the protective assumptions used in this assessment, the benchmarks are protective of avian populations and were based on acute and chronic dietary exposures of northern bobwhite quail and mallard. Toxicological endpoints included mortality, growth, feed consumption, and histopathology. Reproductive endpoints included egg production, fertility, hatchability and survival, and growth of offspring. On the basis of the U. S. Environmental Protection Agency Great Lakes Initiative methodology, and a lowest observable adverse effect concentration (LOAEC) of 10 mg PFOS kg(-1) feed, an uncertainty factor of 36 was derived. The TRV based on PFOS dietary intake was 0.021 mg PFOS kg(-1) body weight day(-1), while for serum, liver, and egg, TRVs were 1.7 microg PFOS mL(-1), 0.6 microg PFOS g(-1) wet weight, and 1.7 microg PFOS mL(-1), respectively. On the basis of the European Commission methodology, a correction factor of 2 (for lowest observed effect level to no observable effect level) and an assessment factor of 30, for a total adjustment of 60, were used to derive PNECs. PNECs based on dietary, mean serum, liver, and egg PFOS concentrations were 0.013 mg PFOS kg(-1) body weight day(-1), 1.0 microg PFOS mL(-1), 0.35 microg PFOS g(-1) wet weight, and 1.0 microg PFOS mL(-1), respectively.

Alkanesulfonic Acids↗