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PubMedDate not supplied

[Plasma apolipoproteins AI and B: reference values in the Isère population and determination of individual values].

Reference ranges for apolipoprotein AI and B plasma concentrations were established in a population of unrelated apparently healthy volunteers (138 men and 186 women) living in the region of Grenoble. Apolipoproteins were measured using an immunoturbidimetric assay on a Cobas Fara II analyzer, with reagents and IFCC standardized calibrators from Orion. Apolipoprotein AI mean concentration was higher in women than in men and increased with age in both men and women older than 45. Apolipoprotein B mean concentration was higher in men and increased linearly with age in both sexes. Linear regression analysis was used to determine desirable and high risk values for apolipoproteins AI and B from the guidelines developed by the National Cholesterol Education Program for HDL cholesterol and LDL cholesterol, respectively. Our data indicate that an apolipoprotein AI value of 1.05 g/l is comparable to an HDL cholesterol value of 0.35 g/l. The apolipoprotein B cutpoints of 1.15 g/l for men and 1.05 g/l for women correspond to the accepted LDL cholesterol cutpoint of 1.60 g/l.

Adolescent↗
PubMed2001

Body mass index of 0 to 45-y-old Danes: reference values and comparison with published European reference values.

OBJECTIVES: To generate body mass index (weight/height(2) (kg/m(2)), BMI) reference values for 0 to 45-y-old Danes and compare these with published European reference values. SUBJECTS: A national sample used to generate the current Danish height and weight reference (29 106 measurements made 1965-1977; age 0-21 y; sample I), and four samples from Copenhagen (3391 measurements made 1981-1985; age 7-45 y; samples II-III and 2608 measurements made 1991-1994; age 6-45 y; samples IV-V). DATA ANALYSIS: Using the LMS method, Danish BMI reference values by age and sex were constructed from samples I and II. These were compared with BMI reference values from Sweden (age 6-16 (girls) or 6-19 y (boys)), Germany (6-19 y), UK (0-23 y), and France (0-87 y). Two recently examined but smaller Danish cohorts (samples IV and V) were compared with the reference values to assess the secular trend in BMI. RESULTS: Overall, Danish BMI reference values (samples I and II) fitted best with French reference values and were systematically below UK, Swedish and German reference values. However, the BMI centiles of young adult Danish women were above French reference values and the BMI of Danes was substantially below French and UK reference values during the first months of life. The mean BMI Z-score of the recently examined samples was 0.24 (sample IV, P=0.0001) and 0.15 (sample V, P=0.0001) based on the French reference values and 0.19 (sample IV, P=0.0007) and 0.01 (sample V, P=0.49) based on the Danish reference values. CONCLUSION: For clinical purposes, we recommend comparing the BMI of Danish children and adolescents with the present Danish reference values and the new IOTF cut-off values and comparing the BMI of Danish adults with the WHO cut-off values. For research purposes, cut-off values and national or internationally used BMI reference values may be used, depending on the research questions.

Adolescent↗
PubMed1986

Clinical biochemical values of llamas: reference values.

Fifteen clinical biochemical measurements were done on serum from 64 clinically healthy adult llamas (26 males and 38 females). Values for several of these tests were different from those reported for llamas and from reference values for other domesticated ruminants. Comparison of values between males and females revealed significant differences for several tests. Clinical biochemical values reported in the present study can serve as reference values for adult llamas.

Animals↗
PubMed2000

Need for revisiting the concept of reference values.

The reference values concept has been adopted by health care professionals, including clinical chemists, laboratory scientists, and clinicians and simultaneously by all the official organizations in charge of the establishment of legislation. But the estimation of reference limits, and the evaluation of biological variability need to be improved at the level of the procedures, which are currently too long and too expensive and not feasible easily for all laboratories. The procedures for obtaining reference values, if we follow the original documents, are complex, and that is the main reason that clinical chemists or diagnostic kit manufacturers have not used them systematically. There is clearly a need that scientific societies and international organizations propose practical recommendations: 1) Recommendations to describe methods linked to systematic error. * How to transfer reference limits from one laboratory to another laboratory using different methods? * Should we determine reference limits for each method? * How can we differentiate bias due to the populations from these due to the method? Clear collaborations with manufacturers involved in kits and diagnostic systems are needed. 2) Practical recommendations linked to the reference population. * How to select a homogeneous population? (Careful recommendations on the choice between healthy individuals, blood donors and individuals hospitalised for other diseases should be given.) * How to estimate ethnic differences? * How to define the exclusion and inclusion criteria according to quantity? * How to deal with the question of reference limits for unstable periods, aging or old people particularly, when the difference between aging and disease is very difficult to define? 3) Practical recommendations on the statistical methods to be used. * How to make a good choice of the interquartile interval? Should we use and present only the centiles 2.5 or 97.5, or on the contrary should we give other centiles in addition, for example 5, 10, 75, 80, 85, 90? 4) Practical recommendations linked to the use of the concept of the reference values. * How to make this concept more concrete and to have official definitions which are better understandable and not only abstract? * How to demonstrate the value of using simultaneously reference limits and decision limits, and what does each of these limits bring to results interpretation? * How to improve the presentation of the results? How to give more information on biological variability in the laboratory data, taking into account the scientific validity of their determination? Should we use new information techniques and new communication systems for reaching these objectives? The responses to all these questions could only be provided if there is a concerted effort at the international level. Practical recommendations should be given, which would be very useful for a better understanding and use of reference values by laboratory scientists and clinicians.

Clinical Chemistry Tests↗
PubMed1987

Recommendation for collection of skin puncture blood from children, with special reference to production of reference values.

Reliable reference values need to be collected under standardized conditions. In order to enable comparison of values observed on patients with reference values, it is also desirable to use the same standardized conditions on patients. The present recommendation was produced as a joint effort of representatives of the clinical chemists and paediatricians of Scandinavia and describes the following details. Preparation of the child before specimen collection (food intake, time of day, physical activity, posture, environment), preparation of skin puncture site (warming, disinfection, ointment), instruments for blood collection (lancet, blood collection vessel), site of puncture (plantar surface of foot, finger, ear lobe), collection of emerging blood and handling and storage of the specimen.

Adolescent↗
PubMed1978

[Reference values of respiratory parameters in adults 4th paper: reference values for screening parameters of lung mechanics (author's transl)].

Reference values for screening parameters, evaluating the shape of flow-volume-curves on forced expiration, were calculated from measurements in 1127 healthy subjects aged between 13 and 72 years. The following parameters were determined by means of the electronic spirometer pneumo-test: 1. the peak flow value Vmax, 2. the whole time constant tauges of the flow volume diagram and its components tau1 and tau2 from the upper and the lower part of the flow volume curve, 3. the most frequent time constant taumax in the distribution function of time constants. In relation to age Vmax-values show a maximum at 35 years and a significant decrease in younger and older subjects. Values in women are significant smaller than in men throughout the range of age. The time constants tauges and tau1 decrease significantly with increase in age. Differences between females and males are not statistically significant for these parameters. The time constants tau2 and taumax are age-independent. Their mean values are identical in all age decades and in women significantly smaller than in man.

Adolescent↗