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PubMed2001

The relationship between the reference value of erythrocyte sedimentation rate and geographical factors.

In order to provide a scientific basis for a unified standard of the reference value of erythrocyte sedimentation rate (ESR) in China, the reference value of healthy people's ESR has been collected. The relationship between the reference value of ESR and geographical factors is examined in this paper. Altitude is the most important factor affecting the reference value of ESR, which decreases with increasing altitude; the relationship is quite significant. The method of stepwise regression analysis was used to deduce two regression equations: Y1 = 12.08 - 0.00222X1 + 0.00114X5 +/- 2.95, Y2 = 18.81 - 0.00323X1 + 0.239X4 +/- 4.70. If the geographical factor value of a particular area in China is known, the reference value of ESR of Chinese people can be calculated by means of the regression equations. Furthermore, the dependence on geographical factors in China can be classified as six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast.

Adult↗

PubMed1984

Reference values: are they useful?

To answer the question of whether reference values are useful in clinical decision-making, this article addresses the following major controversies: (1) Are reference subjects representative of the group from which they are selected? (2) To what extent should the process of collecting reference values be standardized and controlled? (3) Can a single distribution of reference values be used in an meaningful way in the process of clinical decision-making.

Clinical Laboratory Techniques↗

PubMed1997

Reference values of common blood chemistry analytes in healthy population of Rawalpindi-Islamabad area.

The reference values of common blood chemistry analytes in healthy population, aged newborn to 80 years, of Rawalpindi Islamabad area were determined at AFIP, Rawalpindi. A total of 2115 healthy subjects, 1206 males and 909 females, were included in the study. Plasma glucose was analysed by GOD/POD, serum cholesterol by CHOD/PAP, triglycerides by GPO/PAP, urea by urease/GLDH, creatinine by Jaffe' rate reaction, uric acid by uricase, total bilirubin by Jendrassik and Grof, total protein by biuret, alanine transaminase (ALT) by optimized IFCC and alkaline phosphatase (AP) by optimized DGKC method. The between batch CVs of all the parameters were within acceptable quality goals. The reference values were calculated using 2.5 and 97.5 percentiles as lower and upper limits (95% CI). In healthy adult males the reference values were: fasting plasma glucose, 3.6-6.0 mmol/l; serum cholesterol; 3.2-6.6 mmol/l; triglycerides, 0.6-2.3 mmol/l; urea, 2.8-6.4 mmol/l; creatinine, 65-132 umol/l; uric acid, 164-430 umol/l; total bilirubin, 5-18 umol/l; total protein, 57-83 g/l; ALT, 15-45 U/l and AP, 185-620 U/l. The values in adult females, children and elderly subjects were slightly different than adult males. The reference values of our population show mild to moderate differences from the other Asian, European and American populations. It is recommended that reference values of different biochemical investigations should be established in various areas of Pakistan to make appropriate use of such investigations.

Adolescent↗

PubMed1978

Hematology and clinical chemistry reference values for C57BL/6 X DBA/2 F1 mice.

We have analyzed hematology data from 504 individual male C57BL/6 X DBA/2 (hereafter called B6D2F1) mice. Clinical chemistry data from an additional 304 individual male B6D2F1 mice have also been analyzed. The mice had served as drug-diluent controls in 24 toxicological evaluations of anticancer drugs administered singly or in combination. The studies were carried out under standardized conditions during an 18-month period between July 1975 and December 1976. Test values corresponding to 9 percentiles have been selected from an ordered ranking of values for each of 18 hematologic tests and 18 clinical chemistry tests. Since 95% of the values for a given test are found between the 2.5th and 97.5th percentiles, test values corresponding to these percentiles provide reference values ("normal" values) for these mice. The other percentiles (5th, 10th, 25th, 50th, 75th, 90th, and 95th) indicate the distribution of values between the reference limits for each test. Since values for all tests do not conform to the Gaussian distribution, this nonparametric analysis provides reference values that are more accurate than might be obtained from calculation of the mean and standard deviation of a given test. The B6D2F1 mouse, commonly referred to as BDF1, has been widely used for preclinical evaluation of anticancer drugs, and these data should be useful to investigators who are conducting qualitative and quantitative toxicity evaluations in these mice.

Animals↗

PubMed1995

Subject-based reference values.

Medical decisions based on comparison with group-based reference value have often less than desired sensitivity to significant changes in the biochemical or physiological state of an individual under investigation. Subgrouping of the reference values according to sex, age, or other criteria does frequently not solve this problem. The better solution is to compare new values with old results from the same individual, i.e., with subject-based reference values. Two types of criteria may be used: those based on critical differences between two results (the reference change limit) and those based on time-series models.

Clinical Laboratory Techniques↗

PubMed1978

Measurement of reference values for certain proteins in cerebrospinal fluid.

Reference values are presented for certain cerebrospinal fluid proteins and related indexes, based on determinations carried out on 46 patients with diffuse lower back pain using radial immunodiffusion and electroimmunoassay. A sex difference was noted in total protein and albumin values. The electroimmunoassay method with its sensitivity enhanced by the use of Coomassie Blue staining and optimal antiserum concentrations enabled a reference value to be determined for IgA in cerebrospinal fluid.

Adult↗

PubMed2001

Body mass index reference values (mean and SD) for Swedish children.

UNLABELLED: Body mass index (BMI) is an important indicator of nutritional status. Many studies have been done to present BMI reference values in centile values rather than mean and SD values since its statistical distribution is positively skewed. Both height and weight growth charts are usually available in terms of mean and 1, 2 and 3 SD around the means; it would be of clinical value to produce BMI reference charts in a similar way. The aim of this work was to derive the mean and +/- 1, 2 and 3 SD BMI reference ranges as a supplement to the BMI centile reference values published previously for the same group of Swedish children. The method was based on an age-dependent Box transformation, and the beta-value was given as a third-degree polynomial function over the paediatric age. The BMI reference values can be given from mathematical functions in addition to values for specific ages. CONCLUSION: The BMI reference values and charts derived as described effectively reflect the nature of the variant age-dependent positive skewed statistical distribution of BMI values in the population, and can serve as a valid supplementary tool in the evaluation of growth and nutrition during paediatric years.

Adolescent↗

PubMed1994

Estimation of pooled reference values for cadmium in blood using meta-analysis and TRACY criteria.

Reference values for blood-cadmium levels (B-Cd) are available for only a limited number of geographical areas and for particular population strata (sex, age, smoking habits). This paper, in agreement with the TRACY guidelines, describes and discusses the criteria used to rank published papers on reference values for cadmium retrieved by Medline and Toxline between 1976 and 1991. The TRACY criteria deal with the grading of published papers in terms of their suitability for calculating provisional reference values. Only four out of 18 papers were considered suitable for the TRACY project. The four articles were finally used via meta-analysis to provide provisional reference values for smokers and non-smokers. The comparison of results obtained using published statistics and individual data is used to discuss the appropriateness of meta-analysis in the case of cadmium. Due to the availability of large enough studies and to the clear differences across countries, the suitability of a compound upper reference limit to B-Cd levels seems limited.

Adult↗

PubMed1982

[Joint study to establish reference values for clinical chemical parameters in childhood (author's transl)].

The working group 'Pädiatrische Klinische Chemie' undertook a joint study to satisfy the need for more reliable reference values for clinical chemical parameters in childhood. In 15 different pediatric hospitals data for the most important clinical chemical parameters were determined for children of different age groups. The children included in the study fulfilled the required minimal criteria concerning their health state. The data were listed according to parameter and age group and the percentiles and mean values with 95% confidence intervals are presented. From these values, reference ranges are derived that are suitable for daily routine analyses.

Alanine Transaminase↗

PubMed2000

[Hormonal reference values for adrenocortical function in healthy children from Zaragoza].

OBJECTIVE: Estimation of reference values for basal serum concentrations of adrenocorticotropic hormone (ACTH), cortisol, 11-deoxycortisol, 17-OH-progesterone (17-OHP), plasma renin activity (PRA), aldosterone, -4-androstendione ( 4A) and dehydroepiandrosterone sulphate (DHA-S) in healthy children from Zaragoza. METHODS: Reference population were healthy children aged 0 to 14, with normal weight and height, living in the metropolitan area of Zaragoza (Spain). It is a transversal study. Reference values and ranges for ACTH, cortisol, 11-deoxycortisol, 17-OHP, PRA, aldosterone, 4A and DHA-S were estimated, and changes in concentrations were analyzed in relation to age, sex and puberal stage. RESULTS: Reference values have been classified by puberal stage and age in eleven groups for every sex: Tanner I (umbilical cordon, 3 days, 4-30 days, 1-6 months, 6 months-4 years, 4-7 years, 7-10 years, 10-14 years), Tanner II, Tanner III and Tanner IV-V. Sex did not influence ACTH, cortisol, 17-OHP and PRA concentrations, and there are punctual differences in 11-deoxycortisol, aldosterone, 4A and DHA-S levels. 17-OHP, 11-deoxycortisol and aldosterone concentrations significantly decreased from birth to 6 months-4 years and subsequently kept steady. The maximal concentration of ACTH, and ARP in blood cord significantly decreased until the period 6 months-4 years, and subsequent differences among different age groups, and between prepuberal and puberal groups are scarce. The highest concentration of 4A and DHA-S were observed in blood cord and third day of life, decreased until the lowest level in 6 months-4 years and progressively increased with age in prepuberty, and between prepuberty and puberty. The lowest concentration of cortisol was detected in 4-30 days, increased until 6 months-4 years and kept steady along the prepuberty and puberty. CONCLUSION: It is necessary that every population establish own reference values for ACTH, cortisol, 11-deoxycortisol, 17-OHP, PRA, aldosterone, 4A and DHA-S during infancy, childhood and adolescence, according to age, sex and puberal stage.

Adolescent↗

PubMed1989

Steroid profile for urine: reference values.

We describe a project, participated in by 24 institutions in The Netherlands and Belgium, to determine normal reference values for steroids in urine by capillary gas chromatography. Urine samples from 288 healthy volunteers were analyzed in triplicate. Reference values, expressed in mumol/24 h, were determined for androsterone, etiocholanolone, dehydroepiandrosterone, 11-keto-androsterone, 11-keto-etiocholanolone, 11-hydroxyandrosterone, 11-hydroxyetiocholanolone, pregnanediol, pregnanetriol, 11-desoxytetrahydrocortisol, tetrahydrocortisone, tetrahydrocortisol, allo-tetrahydrocortisol, and 17-keto- and 17-hydroxysteroids. We also determined reference ratios for etiocholanolone/androsterone, tetrahydrocortisone/tetrahydrocortisol, and tetrahydrocortisol/allo-tetrahydrocortisol; an upper limit of a discriminant function to establish polycystic ovarian disease; and reference values for 24-h urine volume and creatinine excretion. Reference values were determined separately for men and women, each in six age categories: 0-3 months, 4 months-12 years, 13-16 years, 17-50 years, 51-70 years, and older than 70 years. We conclude that these reference values are reliable and form a basis for quantitative interpretation of steroid profiles.

Adolescent↗

PubMed1996

Selenium and glutathione peroxidase reference values in whole blood and plasma of a reference population living in Valencia, Spain.

In order to assess the reference values for selenium nutritional status, adequate indicators (selenium concentration and glutathione peroxidase activity) were determined in whole blood and blood derivates of a healthy population (n = 287) from the province of Valencia, Spain. The reference population was selected by applying preestablished criteria. Selenium in whole blood and plasma was measured by graphite furnace atomic absorption spectrometry (GFAAS), with a deuterium correction, after addition of Pd/Mg(NO3)2 as the matrix modifier and appropriate dilution. Accuracy was checked by means of a reference material (Seronorm Trace Metals serum and whole blood). The population's reference intervals for selenium content at a 95% confidence level were: 53.03-108.96 and 66.71-119.4 mg/L for plasma and whole blood selenium concentration respectively. GPX activity was measured using a modification of the Paglia and Valentine method, and the reference intervals obtained ranged from 196 to 477 U/L in plasma, from 49 to 93 U/gHb in erythrocytes and from 52 to 96 U/gHb in whole blood. The only statistically significant differences detected between men and women are for to the GPX activity in whole blood. The results obtained are in the range of values found by others authors in healthy populations residing in different European countries.

Adolescent↗

PubMed1982

Lung-function reference values from Victorian power-industry workmen.

Reference values for a number of lung function tests performed on a group of apparently healthy Victorian power industry workmen are described. Most workers in this industry have had at least incidental exposure to a range of respiratory hazards, including asbestos dust, at some time in their working lives, but men who recalled handling asbestos materials were excluded from the study. Comparison with other published Australian data shows considerable variation. Differences such as measurement technique, equipment calibration, occupational factors, and selection bias must be considered when reference values from published reports are used for clinical or epidemiological purposes.

Adult↗

PubMed1990

Method for establishing serum ferritin reference values depending on sex and age.

A method is described for the establishment of reference values for serum ferritin depending on sex and age. The results obtained in a stratified random sample of 353 healthy individuals from the Portuguese population revealed that 23% of the variation observed on serum ferritin values was related to sex differences and 6% of the variation was explained by age differences. Furthermore, the effect of age was different in both sexes: serum ferritin values increase with age in females over 40 years and in males under 40. The minimum and maximum reference values were established for the different subgroups of subjects as follows: for females under 40 years and males over 40, reference values were considered as the 2.5 and 97.5 percentiles from the adjusted lognormal distribution; for females over 40 years and males under 40, reference values were considered as the exponential transformation of the upper and lower limits of the 95% prediction intervals for the log of serum ferritin for each particular age point.

Adolescent↗

PubMed1993

Reference values for organ weight, hematology and serum chemistry in the female ferret (Mustela putrius furo).

Organ Weight, hematologic and blood chemistry values were determined to establish reference values in the female ferret. Organ weight per kg body weight was calculated for various organs. Body surface area (BSA) was also determined by the direct method, and K values (constant) were calculated. The K value was 3.48 in the Dubois and Dubois equation, and 9.69 in the Meeh-Rubner equation. Blood samples were used to record 10 hematologic and 57 serum (plasma) chemistry values, and 7 immunological parameters. Among hematologic values, values whose coefficient of variation (cv) exceeded 30% were RBC, WBC and PLT. In blood chemistry, the CV of gamma-G, UA, ZTT, GPT, gamma-GTP, MAO, ALD and IgG exceeded 30%. In the total amino acid analysis, only the CV of TAU exceeded 30%. Electrophoretograms of amylase and CPK isozyme were quite different from those of humans. Although 1-MEHIS, 3-MEHIS and CAR have not been detected or are present in trace amounts in human plasma, concrete values were detected in female ferret plasma. Hematologic and serum chemistry values were in general agreement with normal values seen in cats and dogs. However, the alpha 1-G percentage, and ALP and amylase activities were lower than the corresponding values in cats and dogs. The RBC count, RET-C percentage and LDH activities were higher than in cats and dogs. Since there have been no comprehensive articles on reference values for the female ferret, the present report contributes to studies that involve this animal as an experimental model.

Alanine Transaminase↗

PubMedDate not supplied

Technical note: reference values of haematocrit in young people and relationship with altitude.

The purpose of this paper is to provide scientific basis for a unified standard reference value of haematocrit in young people in China. The reference values of haematocrit levels in healthy young people have been collected according to the Wintrobe methods; the relationship between the reference values of haematocrit in young people and altitude has been tested in this paper. It has been found that the reference value of haematocrit in young people increases when the altitude gradually increases, and such relationship is quite significant, The method of mathematical univariate regression analysis is used to deduce two regression equations: Y1 = 44.3 + 0.00357X +/- 3.7, and Y2 = 39.7+0.00318X +/- 2.6. If the altitude value of a s known, the particular area of China is known, the reference value of haematocrit in young people there can be calculated by means of the regression equations. Furhermore depending on the altitude, China can be divided into three districts: Qingzang District, Central District and Eastern District.

Adolescent↗

PubMed1990

Reference values: Bhattacharya or the method proposed by the IFCC?

The Bhattacharya method was used to calculate reference values from unselected patient data. These values were compared with reference values obtained from data from a blood donor population group following the recommendations of the IFCC. Differences between the results could be attributed in part to different statistical methods, and in part to differences between populations. With some limitations, the Bhattacharya method can be of help in the determination of reference values and quality control.

Blood Chemical Analysis↗

PubMed1999

Spirometric reference values from a sample of the general U.S. population.

Spirometric reference values for Caucasians, African-Americans, and Mexican-Americans 8 to 80 yr of age were developed from 7,429 asymptomatic, lifelong nonsmoking participants in the third National Health and Nutrition Examination Survey (NHANES III). Spirometry examinations followed the 1987 American Thoracic Society recommendations, and the quality of the data was continuously monitored and maintained. Caucasian subjects had higher mean FVC and FEV1 values than did Mexican-American and African-American subjects across the entire age range. However, Caucasian and Mexican-American subjects had similar FVC and FEV1 values with respect to height, and African-American subjects had lower values. These differences may be partially due to differences in body build: observed Mexican-Americans were shorter than Caucasian subjects of the same age, and African-Americans on average have a smaller trunk:leg ratio than do Caucasians. Reference values and lower limits of normal were derived using a piecewise polynomial model with age and height as predictors. These reference values encompass a wide age range for three race/ethnic groups and should prove useful for diagnostic and research purposes.

Adolescent↗