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PubMed2004

Age related reference values for urine creatine and guanidinoacetic acid concentration in children and adolescents by gas chromatography-mass spectrometry.

A new gas chromatography-mass spectrometry method for routine quantification of urine creatine and guanidinoacetic acid (GAA) has been developed to provide a fast, reliable and inexpensive metabolic screening. Our method uses a two-step derivatization procedure which involves a reaction with hexafluoroacetylacetone followed by a reaction with mono-trimethylsilyltrifluoroacetamide. The standard curves showed linearity over a range of 43-4269 micromol/l for GAA and 38-7325 micromol/l for creatine, which covers the range of GAA and creatine normally found in urine. The lower detection limit is 1.54 micromol/l for GAA and 1.22 micromol/l for creatine, whereas the lower quantification limit is 5.04 micromol/l for GAA and 4.19 micromol/l for creatine. This method was also employed to establish reference values for GAA and creatine in healthy infants, children and adolescents based on the analysis of 169 urine samples. Although no sex differences were observed, normal GAA urinary levels and creatine excretion are distinct in age-related subgroups. We identified a statistically significant age difference in two major groups for GAA (children under 4 years, 18-159 micromol/mmol creatinine; and subjects of 5-16 years, 18-130 micromol/mmol creatinine) whereas three groups were discriminated for creatine (children under 4 years, 0.04-1.51 mmol/mmol creatinine; subjects of 5-11 years, 0.04-1.07 mmol/mmol creatinine; and subjects of 12-16 years, 0.04-0.56 mmol/mmol creatinine).

Adolescent↗

PubMed2005

Urinary markers of adrenarche: reference values in healthy subjects, aged 3-18 years.

Information on the urinary excretion of dehydroepiandrosterone (DHEA) and its direct metabolites is scarce for healthy subjects during growth. We used gas chromatography-mass spectrometry urinary steroid profiling to noninvasively study adrenarchal metabolome in 400 healthy subjects, aged 3-18 yr. Urinary 24-h excretion rates of DHEA did not increase significantly before age 7-8 yr. However, DHEA together with its 16alpha-hydroxylated downstream metabolites, 16alpha-hydroxy-DHEA and 3beta,16alpha,17beta-androstenetriol (DHEA&M), as well as the DHEA metabolite, 5-androstene-3beta,17beta-diol (ADIOL), and the sum of major urinary androgen metabolites (C19) rose consistently from the youngest to the oldest age group. The significant increases (P < 0.01) observed for 24-h excretion rates of C19, ADIOL, and DHEA&M were 2- to 4-fold in boys and girls between age 3 and 8 yr. DHEA&M, for example, rose from about 20 to 80 microg/d (P < 0.0001) during this period. Until the age of 16 yr, DHEA&M excretion also increased to nearly 1000 microg/d. Patterns of steroidogenic enzyme activities were assessed (from definite ratios of urinary steroid metabolites) for 21-hydroxylase, 3beta-hydroxysteroid dehydrogenase, 17beta-hydroxysteroid dehydrogenase, and 5alpha-reductase. Our results indicate for healthy boys and girls that adrenarche is a gradual process starting much earlier than hitherto believed. Efficient metabolism of DHEA, especially to 16-hydroxylated steroids, may explain the almost constant levels seen for this steroid until age 7-8 yr. The established reference values for DHEA, DHEA&M, ADIOL, C19 (including androsterone and etiocholanolone), and urinary parameters of steroidogenic enzyme activities could be useful to identify nutritional, environmental, and pathophysiological interrelations with the progressive maturational process of adrenarche. Our data may also be used as reference data for the diagnosis of steroid-related disorders.

3-Hydroxysteroid Dehydrogenases↗

PubMed1990

Reference values for ambulatory blood pressure: a meta-analysis.

The aim of the present study was to perform a meta-analysis of published studies in an attempt to determine the mean and range of normal ambulatory blood pressure. Twenty-two studies, including a total of 2638 subjects, were reviewed. Most studies were compatible with a mean 24-h ambulatory pressure in the range of 115/70-120/75 mmHg, a mean daytime pressure of 120/75-125/80 mmHg and a mean night-time pressure of 105/60-110/65 mmHg. With weighting for the number of subjects included in the individual studies, the 24-h ambulatory pressure averaged 117/72 mmHg, the daytime pressure 122/77 mmHg and the night-time pressure 106/64 mmHg. The night:day pressure ratio averaged 0.87 for systolic and 0.83 for diastolic pressure, ranging from 0.79 to 0.92 and from 0.75 to 0.90, respectively, across the individual studies. With the mean +/- 2 standard deviation intervals in the various studies taken as normal, the range of normality averaged 97/57-137/87 mmHg over 24 h, 101/62-143/91 mmHg for the daytime pressure and 86/48-127/79 mmHg for the night-time pressure. Until the results of prospective studies on the relationship between ambulatory blood pressure and the incidence of cardiovascular morbidity and mortality become available, these estimates of normal ambulatory pressure could be applied as reference values in clinical practice.

Adolescent↗

PubMed2005

[Distribution, determinants and reference values of left ventricular parameters in the general population--results of the MONICA/KORA echocardiography studies].

For successful fighting against the burden of cardiovascular disease in the community a comprehensive knowledge about the prevalence and the impact of underlying risk factors is important. The present paper summarises some studies undertaken on more than 2000 persons from the MONICA/KORA-studies (parts of S1 and S3) where left ventricular mass (LVM) and other left ventricular parameters were determined by echocardiography. We especially investigated the associations of LVM with blood pressure and obesity. A special focus was on sex-specific factors in the determination of LVM and the influence of different indices of body size when normalising LVM. It could be shown that hypertension and obesity are major determinants of LV hypertrophy. Especially women with both hypertension and obesity on showed a high prevalence of concentric hypertrophy, significantly more than men. We also showed that the prevalence of LV hypertrophy in a representative sample of the general population (25 to 74 years) is 17.5 % for men, and 18.5 % for women. This underscores the need for primary and secondary prevention regarding the development of LV hypertrophy. Finally, our data in a selected group of normal subjects (reference sample) may be used for the development of reference values for left ventricular parameters in the general German population.

Adult↗

PubMed1995

[Evolution of breathing pattern and ventilation at maximal exercise during growth. Definition of reference values].

The aim of the study was to define the changes of parameters of breathing pattern and ventilation (VE) as a function of age during maximal exercise in children. A multi-longitudinal survey was conducted in forty four untrained schoolboys, divided in three groups with initial age of 11.2 years for group I, 12.9 years for group II, and 14.9 for group III. These children were subsequently followed three years ago at the same period. The range age was thus 11.2 to 16.9 years. This study showed that, during growth, ventilation (VE max), tidal volume (VT max) and mean inspiratory flow (VT/TI max) increased significantly with age, that inspiratory frequency (f max) decreased, that inspiratory, expiratory and total time of the respiratory cycle (TI max, TE max, TTOT max) increased slightly and that the inspiration fraction (TI/TTOT max) was identical at 11 and 17 years. Furthermore we observed that the peak height velocity and peak tidal volume velocity took place at the same age, i.e., 14 years and that those of weight and VT/TI at the same age of 15 years. In conclusion, this study allowed us to define reference values for breathing pattern at maximal exercise in sedentary boys and to specify the relation between growth and parameters of breathing pattern in these children.

Adolescent↗

PubMed1996

[Kidney function tests in horses--methods and reference values in healthy animals].

Investigations of renal function have been done on the basis of renal clearance (Clr) and excretion (E) of endogenous creatinine in healthy horses of different body weight (23 female, 7 male). Creatinine was measured by enzymatic PAP-method. Creatinine-E of female horses was poor positively correlated with body weight. The creatinine-Clr was highly correlated with the inulin-Clr (r = 0,896, p < 0,001). The excretion of creatinine was 35% higher than the filtration of creatinine, determined by inulin-Clr. That demonstrate a tubular net secretion of 26% of the total creatinine excretion. However the creatinine-Clr may be considered representative enough for the glomerular filtration rate (GFR). Water, sodium, glucose and L-lactate were absorbed in the renal tubules nearly completely, with a fractional excretion (FE) lower 2%. So they are suitable as endogenous markers for insufficient tubular absorption. Other electrolytes were absorbed incompletely depending on the supply of these substances (calcium-FE and magnesium-FE: 1-50%, potassium-FE: 10-120%, phosphate-FE: 0-5%). An extremely variable part of the filtered urea was reabsorbed in the tubuli (urea-FE 8-85%). For that reason urea is not appropriate for the diagnostic of disturbances of renal functions. A method for clinical determination of renal function by measurement of concentrations of metabolites and electrolytes in blood plasma and spontaneous urine is described and evaluated. The method is based on the supposed constant excretion of the creatinine (0,17 mumol/min/kg) and allows especially the examination of male and sick animals without quantitative sampling of urine. Reference-values for the renal excretion of electrolytes and metabolites of healthy horses are given.

Animals↗

PubMed2006

Exhaled nitric oxide in healthy nonatopic school-age children: determinants and height-adjusted reference values.

Exhaled nitric oxide (FENO) was proposed as a marker of airway inflammation, but data about FENO in healthy children measured with standardized methods are so far limited. In order to assess the determinants of FENO in healthy children, we investigated a population-based sample of school-age children (n = 276) with a questionnaire, skin-prick tests, spirometry, and the measurement of FENO. The FENO of 114 nonatopic and nonsmoking children considered healthy were analyzed with stepwise multiple regression analysis, which showed significant associations with age, standing height, weight, and body surface area, but not with gender. Height was found to be the best independent variable for the regression equation for FENO, which on average showed an increase in the height range of 120-180 cm from 7 to 14 ppb. In the random sample of children, increased FENO was associated with atopy (odds ratio, 9.0; 95% confidence interval, 3.9-21.1; P < 0.0001), and significantly with allergic rhinitis and atopic dermatitis, but not with asthma. Respiratory symptom-free children with skin-prick test positivity had significantly higher FENO than healthy nonatopic subjects. We conclude that height is the best determinant of FENO in healthy children. Due to the strong effect of atopy, FENO data should not be interpreted without knowing the atopic status of the child. The present reference values of FENO may serve in clinical assessments for measuring airway inflammation in children.

Adolescent↗

PubMed1992

Importance of establishing appropriate local reference values for the screening of hemochromatosis: a study of three different control populations and 136 hemochromatosis family members. Hemochromatosis Clinical and Research Group.

Hemochromatosis is a human leukocyte antigen-linked (HLA-linked), potentially lethal disorder of iron metabolism with a high prevalence in white populations albeit an autosomal recessive mode of transmission. The diagnosis and treatment at early stages of the disease are critical to the prevention of the morbidity and mortality caused by the iron overload. After the identification of the first cases of hemochromatosis in Portugal, a screening program was started with a systematic search for the disease among family members of the patients, as well as in subjects from the normal population. In this study we analyze the results obtained with a total of 136 family members from 15 different families and 353 control subjects from three different villages, two in the north and one in the south of Portugal. We establish reference values for the biochemical tests used in the screening for iron overload and analyze the factors that affect those results. Besides sex-related differences, factors that were found to influence biochemical parameters most significantly included age and levels of daily alcohol intake. In addition, differences in iron status were identified between the populations from the regions in the north and the south of the country. We estimate, by HLA typing and family studies, a gene frequency for hemochromatosis of 0.14 that corresponds to a frequency of homozygotes and heterozygotes of 0.019 and 0.24, respectively.

Adolescent↗

PubMed1994

Home blood pressure: variability, comparison with office readings and proposal for reference values. Groupe de la Mesure, French Society of Hypertension.

PURPOSE: A multicentre study was performed on 390 healthy subjects (210 male, 180 female) to evaluate home blood pressure versus office blood pressure. METHODS: The patients, aged 20-59 years, not on antihypertensive treatment, were not preselected by blood pressure levels. Blood pressure was measured in the doctor's office, using a mercury manometer at the fifth, sixth and seventh minute of rest, and at home by self-measurement using a validated electronic oscillometric device at the fifth, sixth and seventh minute of rest, in the morning and evening, on three consecutive days. RESULTS: The analysis of office and home measurements at the fifth, sixth and seventh minute of rest showed a significant decrease in blood pressure, mostly between the fifth and sixth minute. There was no significant variation in home pressure over the three consecutive days of measurement. Blood pressures were significantly higher in the evening than in the morning; the mean differences were 3 mmHg for systolic and 1.5 mmHg for diastolic blood pressure. Compared with office blood pressure measurement, home measurement provided significantly lower systolic and diastolic blood pressure means. Of the subjects, 78% showed a higher systolic and 69.9% a higher diastolic blood pressure with office measurement than with home measurement. Systolic and diastolic blood pressure differences were non-significantly higher for females than for males and did not differ with age. CONCLUSIONS: The comparison of the office and home measurement distributions allowed us to propose reference values for home blood pressure measurement. These were established by choosing blood pressure at the identical percentile for home measurement as we found for office measurement using the World Health Organization criteria (140/90 and 160/95 mmHg). Using this approach, the upper limit for normotension by home measurement would be 127/83 mmHg and for hypertension 147/86 mmHg. Although this approach has no prognostic value, it could be useful for the interpretation of home blood pressure.

Adult↗

PubMed2006

Determination of dichloroanilines in human urine by gas chromatography/mass spectrometry: validation protocol and establishment of Reference Values in a population group living in central Italy.

3,4- and 3,5-Dichloroanilines (DCAs) are common markers of some non-persistent pesticides, e.g. linuron, diuron, vinclozolin, and iprodione. The general population may be exposed to these DCAs and/or their precursors mainly through diet. Since adverse effects on human health, such as endocrine disruption, have been reported, biological monitoring is essential for exposure assessment both of occupationally exposed subjects and of the general population. A highly sensitive and selective gas chromatography/mass spectrometry (GC/MS) method has been developed for the determination of 3,4- and 3,5-DCAs in urine using 4-chloro-2-methylaniline as an internal standard. The selected ion monitoring (SIM) mode was employed for quantitation of the analytes. The sample treatment procedure is simple and fast and no derivatization is required. The overall method was validated including uncertainty measurement. The limit of detection (LOD) and the lower limit of quantitation (LLOQ) were determined to be 0.005 and 0.010 microg/L for both analytes. The method was then applied to the establishment of reference values for a population group living in a rural area of central Italy (Novafeltria, Marche). A total of 151 out of 153 samples were found to be positive for 3,5-DCA, and 81.7% were positive for 3,4-DCA. For this group, 3,4-DCA levels ranged from 0.01 to 6.19 microg/L, while 3,5-DCA urinary concentrations were between 0.02 and 6.71 microg/L.

Aniline Compounds↗

PubMed2003

Reference values for an index of fetal aortic isthmus blood flow during the second half of pregnancy.

OBJECTIVE: During fetal life, the parallel position of the two cardiac ventricles confers a special status to the aortic isthmus. Flow through the isthmus reflects the balance between the performances of the two ventricles and their respective peripheral impedances. This study proposes a fetal aortic isthmus flow velocity index and its reference values defined on the basis of gestational age (GA). METHODS: Video recordings of 111 normal fetuses from 18 to 39 weeks of gestation were retrospectively reviewed. An isthmus flow velocity index (IFI) was calculated as follows: IFI = (systolic + diastolic)/systolic velocity integrals. GA-specific reference ranges of IFI were constructed. RESULTS: An IFI of 1.33 +/- 0.03 was found at 18 weeks. This value decreased slightly but steadily with GA to reach 1.23 +/- 0.16 at 39 weeks. This change is mainly related to a decrease in diastolic velocity integrals. CONCLUSION: The proposed IFI provides information on the direction and, indirectly, on the volume of blood flow through the fetal aortic isthmus.

Aorta, Thoracic↗

PubMed1985

[Immunophenotyping of lymphocyte subpopulations using monoclonal antibodies in an analytical flow cytometer: evaluation of the method and reference values].

Analytical flow cytometers which are easy to operate, and monoclonal antibodies specific for cell surface determinants of lymphocytes, offer a simple and rapid method for the identification of the immunological phenotype of lymphocyte subsets. We investigated mononuclear cells isolated from EDTA-blood bv density gradient centrifugation. The intraassay precision (n = 12) of the determination by means of monoclonal antibodies directed against T-cells (Leu 4), T-helper/inducer-cells (Leu 3 a, b), T-suppressor/cytotoxic cells (Leu 2 a) and cells of the 'NK'-phenotype (Leu 7) varied between 2.2 and 7.9%. Studies using the subset markers Leu 2a and Leu 3a, b conjugated either to fluorescein isothiocyanate (FITC) or to phycoerythrin (PE) showed comparable results for both subsets. Dual immunofluorescent analysis using two different antibodies conjugated to contrasting fluorochromes resulted in slightly higher fractions of T-helper/inducer-cells (Leu 3a, b-FITC: a = 0.97, b = 3.18, r = 0.98) and T-suppressor/cytotoxic cells (Leu 2 a-PE: a = 0.99, b = 2.22, r = 0.97) compared with single immunofluorescent analysis. We found no constant association to explain this statistically significant discrepancy (p less than or equal to 0.0002). The investigation of 100 controls established the following reference values for the fraction of lymphocyte subsets (median, 95%-interval): T-cells 0.75 (0.57-0.87), T-helper/inducer-cells 0.47 (0.34-0.63), T-suppressor/cytotoxic cells 0.26 (0.15-0.42), 'NK'-cells 0.16 (0.04-0.34). The corresponding absolute numbers of cells are: T-cells 1.300 (0.730-2.240), T-helper/inducer-cells 0.820 (0.44-1.540), T-suppressor/cytotoxic cells 0.450 (0.190-0.915), 'NK'-cells 0.300 (0.060-0.670).

Adult↗

PubMed1984

Reference values and age-related trends for arm muscle area, arm fat area, and sum of skinfolds for United States adults.

Age- and sex-specific percentile distributions for mid-upper arm muscle area (AMA), mid-upper arm fat area (AFA), subscapular skinfold thickness, and sum of triceps and subscapular skinfold thickness for United States adults (18-74 yr) were developed from cross-sectional data collected by the National Center for Health Statistics (NCHS) during the Health and Nutrition Examination Survey, 1971-1974 (NHANES I). Sample weighting factors were applied to the data to assure the production of the identical data set used to calculate weight-for-height percentiles by NCHS. Smoothed curves developed from the percentile distributions for AMA and AFA are also presented. Arm muscle area and AFA were calculated from the Health Examination Survey of 1960-1962 (HES) which made possible an age-cohort analysis for age-related changes and secular trends. Secular differences were found for arm muscle area for both men and women, while men differed little in fat-related anthropometric parameters. The secular change in arm fat area for women could be explained by the greater amount of fat that surrounded a larger arm, since the ratio of AFA to AMA did not change between the two surveys. Age-cohort analysis revealed increases in AMA with age rather than the apparent decrease observed for the older age groups in the cross-sectional data. Reference values developed from the most recent cross-sectional data are the most appropriate for the nutritional assessment of United States adults, because each age cohort can be seen to display different anthropometric characteristics as well as age-related changes in these parameters.

Adipose Tissue↗

PubMed2006

The electrocardiogram of the Beagle dog: reference values and effect of sex, genetic strain, body position and heart rate.

The aim of the study was to establish a database for electrocardiographic parameters of Beagle dogs used for toxicological studies and to evaluate the influence of supplier, sex, heart rate (HR) and body position for electrocardiogram (ECG) recording on ECG parameters. Peripheral ECG leads were recorded from 934 female and 946 male dogs from Marshall Farms and 27 females and 30 males from Harlan, either standing on a table or restrained in a hammock. HR, RR, PQ and QT intervals, P and QRS duration and P-wave amplitude were measured. There were no major differences between sexes for ECG parameters. The axis of the heart was shifted to the left when the animals were restrained in a hammock compared to when they were standing on a table. The PQ interval was higher (about 9%) in Harlan than in Marshall dogs. HR was negatively correlated with QT (coefficient of linear correlation: r=-0.61 to -0.74), which emphasizes the need for a formula correcting QT interval for HR when interpreting changes in QT interval. HR was also negatively correlated with PQ intervals (r=-0.26 to -0.11), whereas a positive correlation was found between HR and the amplitude of the P wave (r=0.21-0.34). The level of the respiratory sinus arrhythmia (SA) was quantified by calculating the ratio of maximum to minimum RR interval measured over a 10 s period. This ratio was negatively correlated with HR (r =-0.49 to -0.33). Therefore, at high HRs, SA was less marked than at low HRs, but it did not completely disappear. Analysis of beat-to-beat variation indicated that QT and PQ intervals and the amplitude of P wave fluctuated over time and the degree of this variability was positively correlated with the level of SA. In conclusion, we have established reference values for the duration and/or amplitude of some ECG parameters both in terms of means and variability over the recording period, and we have evaluated the influence of body position, genetic strain and HR on the ECG parameters. These data can be used as baseline for the interpretation of the ECG of Beagle dogs.

Animals↗

PubMed1999

Reference values of plasma apolipoproteins A-I and B, and association with nonlipid risk factors in the populations of two Canadian provinces: Quebec and Saskatchewan. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To determine the population distribution of apolipoproteins A-I and B, and the relationship of apolipoprotein B to lipid risk factors for coronary artery disease. DESIGN: A stratified random sample of men and women aged 18 to 74 years selected from the provinces of Saskatchewan and Quebec in 1989 and 1990. OUTCOME MEASURES: Plasma concentrations of apolipoproteins A-I and B, triglycerides, low density lipoprotein cholesterol, high density lipoprotein cholesterol and nonhigh density lipoprotein cholesterol for subjects who provided a fasting blood sample. MAIN RESULTS: Apolipoprotein B mean values increased with age from 0.80 g/L at age 18 to 24 years to a maximum of 1.16 g/L in the 45 to 54 year age group for men. For women, the values increased more gradually from 0.81 g/L for ages 18 to 24 to 1.19 g/L at ages 65 to 74 years. The distribution of apolipoprotein A-I was unrelated to age. Means for men varied from 1.35 g/L to 1.42 g/L and for women from 1.50 g/L to 1.61 g/L. Apolipoprotein B was strongly correlated with nonhigh density lipoprotein cholesterol (r2=0.89), and this was used to define apolipoprotein B concentrations less than 1.04 g/L as indicating low risk for coronary artery disease, from 1.04 g/L to less than 1.22 g/L as moderate risk, from 1.22 g/L to less than 1.40 g/L as high risk, and 1.40 g/L or greater as very high risk. The prevalence of high risk plasma apolipoprotein B levels was higher in men and women with triglycerides greater than 2.3 mmol/L. Apolipoprotein A-I was strongly correlated with high density lipoprotein cholesterol (r2=0.67), and this was use to identify apolipoprotein A-I concentrations of less than 1.20 g/L as a risk factor and 1.65 g/L or greater as an antirisk factor for coronary artery disease. The prevalence of apolipoprotein A-I of less than 1. 20 g/L was 19% in men and 6% in women, whereas the prevalence of apolipoprotein AI 1.65 g/L or greater was 9% in men and 28% in women. CONCLUSION: Reference values for plasma apolipoproteins A-I and B in a Canadian population random sample are given. Plasma apolipoprotein B and apolipoprotein A-I provide information that is complementary to that provided by low density lipoprotein and high density lipoprotein cholesterol levels.

Adolescent↗

PubMed2003

Measures of cardiovascular autonomic nervous function: agreement, reproducibility, and reference values in middle age and elderly subjects.

AIMS/HYPOTHESIS: Currently, three categories of cardiovascular autonomic nervous function measures are used: classic Ewing-test measures, measures of heart-rate variability (HRV), and measures of baroreflex sensitivity (BRS). Little is known about the agreement between these measures, and reference and reproducibility values for these measures have not been reported within the same group. METHODS: As part of the Hoorn Study, 631 subjects aged 50 to 75 participated in a study of autonomic nervous function. Cardiac cycle duration (RR interval) and continuous finger arterial pressure were measured under three conditions: during spontaneous breathing, during six deep breaths over 1 min, and during an active change in position from lying to standing. From these readings, ten measures of autonomic function were assessed (mean heart rate, three Ewing test measures, five HRV measures and one BRS measure). RESULTS: Regression analysis in a healthy subgroup (n=191) showed sex differences for two of the ten measures and seven measures decreased with age. Therefore, appropriate age-specific and sex-specific reference values were calculated. Reproducibility (n=39) of most measures was moderate, with a reliability coefficient of around 50%. Agreement between the measures of autonomic nervous function varied greatly, between 0% and 87%. The HRV-power ratio measure and the blood pressure changes in the lying-to-standing test showed the lowest agreement with all other measures. CONCLUSION/INTERPRETATION: This study provides age-specific and sex-specific reference values for a wide range of different autonomic function measures in an elderly population. Agreement among the different measures varied widely and reproducibility was only moderate.

Aged↗

PubMed1999

Reference values of total serum IgE and their significance in the diagnosis of allergy among the young adult Kuwaiti population.

BACKGROUND: The reference total serum immunoglobulin (IgE) values and the usefulness of total IgE values in the diagnosis of allergy have not been established for the Kuwaiti population. The literature reference values may not be applicable since such values often vary among ethnic nationalities. OBJECTIVE: The aim of this study was to establish the reference IgE values for the young adult Kuwaiti population and to determine the usefulness of such values in the diagnosis of allergic diseases in the community. METHODS: A total of 1057 randomly selected young adults were screened for atopy using the Pharmacia CAP-PhadiatopR method. Atopy was detected in 423 individuals (40.0%). Total serum IgE was then measured in 542 randomly selected Phadiatop-negative (non-atopic) cases in the age range 18-50 years (mean 28.9 years) and male:female ratio of 1.3. RESULTS: Serum total IgE values in non-atopics covered a very wide range (< 2-1993 kU/L) with a geometric mean (GM) value of 43.7 kU/L. The reference range, calculated as the 95% confidence interval of the log IgE (95% CI) was 3.2-602.5 kU/L. The 90% CI was 11.7-162 kU/L. The GM was significantly higher for males than females, (53.7 vs. 35.5 kU/L, P < 0.001) and for smokers than non-smokers, (64.6 vs. 40.7 kU/L, P < 0.01), but was independent of age. Although the GM for the non-atopics (43.7 kU/L) was significantly lower than those of the asymptomatic atopics (213.8 kU/L) and allergic asthmatics (626.6 kU/L), the 95% CI for the three groups showed considerable overlap. CONCLUSIONS: These results show that the normal total IgE values in the young adult Kuwaiti population are generally high and that the distribution of the values is so wide that the diagnostic value of total serum IgE in this community is likely to be very limited.

Adolescent↗

PubMed2001

A review of tissue reference values used to assess the trace element status of farmed red deer (Cervus elaphus).

AIMS: This paper reviews the principles for the establishment of biochemical reference criteria for assessing the trace element status of farmed livestock and summarises data for copper, selenium, vitamin B12 and iodine for farmed red deer. COPPER: Enzootic ataxia and osteochondrosis occur when liver copper concentrations are below 60 micromol/kg fresh tissue, and serum copper concentrations are below 3-4 micromol/l. Growth responses to copper supplementation have been equivocal when blood copper concentrations were 3-4 micromol/l, but were significant when mean blood copper concentrations were 0.9-4.0 micromol/l. No antler growth or bodyweight response to copper supplementation was observed when blood ferroxidase levels averaged 10-23 IU/l (equivalent to serum copper concentrations of 6-13 micromol/l) and liver copper concentrations averaged 98 mumol/kg fresh tissue. These data suggest that 'deficient', 'marginal' and 'adequate' ranges for serum copper concentrations should be 5, 5-8, and 8 micromol/l, respectively, and those for liver copper concentrations should be 60, 60-100, and 100 micromol/kg, respectively. SELENIUM: White muscle disease has been reported in young deer with blood and liver selenium concentrations of 84-140 nmol/l and 240-500 nmol/kg fresh tissue, respectively. No growth-rate response to selenium supplementation occurred in rising 1-year-old deer when blood selenium concentrations were less than 130 nmol/l, the range in which a growth-rate response would be expected in sheep. VITAMIN B12: Vitamin B12 concentrations in deer are frequently below 185 pmol/l without clinical or subclinical effects. No growth response was observed in young deer with vitamin B12 concentrations as low as 75-83 pmol/l. A growth response to cobalt/vitamin B12 supplementation occurs in lambs with serum vitamin B12 concentrations 336 pmol/l. CONCLUSIONS: Data that can be used to establish reference ranges for assessing trace element status in deer are limited. More robust reference values for farmed red deer need to be established through further studies relating biochemical data to health and performance.

Journal Article↗