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PubMed1988

Reference values for pulsed Doppler signals from the blood flow velocity on both sides of the pulmonary valve.

Pulsed Doppler signals were recorded from the pulmonary artery and the right ventricular outflow tract in 215 healthy subjects (120 males, 95 females; 1-65 years). Amplitude spectra from these Doppler signals were stored in digital form together with adjustment data for the instrument and the simultaneously recorded ECG. From these Doppler spectra the median of the maximal velocity (Vmax), the maximal acceleration (Amax) and the dispersion of the velocity distribution around Vmax (width) were calculated. These three median values were used to characterize the Doppler spectra and to define normal values for bloodflow velocities. Thus, calculations were made without observer interacting using a well-defined computer program. The effect of age, gender, body surface area and heart rate were studied. Reference ranges were calculated. There is a slight decrease of the median value of Vmax and Amax in the pulmonary artery during lifetime from 80 to 70 cm s-1 and from 1,200 to 800 cm s-2, respectively. On the other hand, there is no correlation between age and Vmax and Amax in the right ventricular outflow tract. The width of the spectra increases with age at both sites. No significant changes with age were seen with the other variables.

Adolescent↗
PubMed1987

[Ambulatory blood pressure in normotensive subjects. Definition of reference values as a function of age by the Spacelabs instrument].

For a finer assessment, by repeated blood pressure (BP) measurements, of the cardiovascular risk associated with BP levels, new instruments have been developed which provide multiple reading during periods of activity. However, the lack of epidemiological studies makes it necessary to determine reference ambulatory BP levels by another method. Twelve-hour recordings were taken with the Spacelabs instrument in 130 volunteers (45% males) aged from 20 to 90 years during their various activities. Mean systolic and diastolic BP values +/- SD were calculated per age-groups of 10 years each. That this sample was representative of the general population was confirmed by the fact that BP fluctuations and variations according to age and sex in these 130 subjects were identical with those observed in the population of an entire town (Framingham). The concept of hypertension, as defined by ambulatory BP recordings, is discussed. This study provides, for the first time, reference ambulatory BP values according to age and sex, measured in normotensive subjects with the Spacelabs instrument. These values constitute a preliminary step indispensable to evaluate this technique in hypertensive patients.

Adult↗
PubMed1979

Urinary total porphyrins by ion exchange analysis: reference values for the normal range and remarks on preformed prophyrins in acute porphyria urine.

Determination of total porphyrin with a rapid and east method (ion exchange; spectrophotometry) was performed on 57 morning urine samples from laboratory personnel, 59 arbitrary day urine samples from blood donors, and 90 24-hour urines from medical inpatients. The upper reference limit for morning urine was 0.32 mumol/l but even a value as high as 0.7 mumol/l was found. In the donor urines the upper limit was 0.155 mumol/l. The 24-hour urines showed an upper reference limit of 271 microgram/24 h. These values are in good agreement with values from the literature, mostly based on extraction analyses. Tracings of the absorption curves in the region of 380--430 nm were performed in all analyses and showed that the non-porphyrin absorption was close to linear in most cases. Studies of porphyric urines gave no support to the claim that preformed porphyrins not formed from porphobilinogen are excreted in this disease.

Acute Disease↗
PubMed1978

Hematologic and serum protein reference values of the Octodon degus.

Blood and serum from normal degus (Octodon degus) that ranged in age from 3 to 48 months were analyzed to determine reference hematologic and serum protein values. Both sexes were evaluated and were similar. The hematologic and serum protein values for males were: erythrocytes, 8.69 +/- 0.19 X 10(6) /microliter; packed cell volume, 42.1% +/- 0.59%; hemoglobin, 12.0 +/- 0.15 g/dl; leukocytes, 8.50 +/- 0.39 X 10(3)/microliter; neutrophil-to-lymphocyte ration, 40:60; and total protein, 5.70 +/- 0.20 g/dl. The hematologic and serum protein values for females were: erythrocytes, 8.94 +/- 0.16 X 10(6)/microliter; packed cell volume, 40.0% +/- 0.61%; hemoglobin, 11.7 +/- 0.17 g/dl; leukocytes, 8.20 +/- 0.36 X 10(3)/microliter; neutrophil-to-lymphocyte ratio, 40:60; and total protein, 5.62 +/- 0.18 g/dl. The hematologic and serum protein values for the degu were similar in some respects to values reported for guinea pigs and rats.

Animals↗
PubMed1983

[Acid phosphatase in blood (substrate: alpha-naphthylphosphate): reference values and diagnostic significance].

We report the results obtained with a modification of Hillmann's method (1) for determination of the catalytic concentration of acid phosphatase in serum using alpha-naphthylphosphate as the substrate. In a group of 158 males aged 16-85 years, the upper limit of the reference range (95th percentile) for the total acid phosphatase was established as 4.7 U/l (37 degrees C) and 4.2 U/l (30 degrees C), respectively; the corresponding values for the tartrate-inhibited acid phosphatase were 1.6 U/l (37 degrees C) and 1.5 U/l (30 degrees C). The upper limit of the reference range (95th percentile) for the total acid phosphatase determined in 60 females aged 18-80 years was 3.7 U/l (37 degrees C) and 3.0 U/l (30 degrees C). The catalytic concentrations in men and women did not show any age-related differences. The catalytic concentration of the tartrate-inhibited acid phosphatase was determined with the substrates alpha-naphthylphosphate and p-nitrophenylphosphate in a group of 89 patients with prostatic carcinoma (stages C and D). In 74 of these patients, the concentration of the prostatic specific acid phosphatase was assayed by enzyme-immunoassay and radioimmunoassay. The sensitivity of the method with p-nitrophenylphosphate was found to be unsatisfactory (66%), while that obtained with the other methods was superior and intercomparable (approx. 90%). The results obtained with the two substrates (p-nitrophenylphosphate vs. alpha-naphthylphosphate) differed significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1988

Urinary lipoperoxides quantified by liquid chromatography, and determination of reference values for adults.

Urinary lipoperoxides, measured as the malondialdehyde-thiobarbituric acid adduct, were quantified by adapting to urine the liquid-chromatographic method of Wong et al. (Clin Chem 1987;33:214-20) to plasma. Reference intervals for untimed urine specimens from 121 men, ages 16 to 67 years, and 107 women, ages 15 to 55, were determined. Their concentrations differed significantly (P = 0.015), males having a mean (and SD) of 0.89 (0.35) nmol of malondialdehyde per milligram of creatinine, females 0.78 (0.30). In both groups, the values were slightly skewed to the higher values. Our early studies suggest that measuring urinary lipoperoxide may have advantages over plasma in studying certain disorders. The presence of other urinary chromophores or TBA-reactive substances stresses the need for chromatographic techniques when lipoperoxides are measured in biological samples.

Adolescent↗
PubMed1988

Serum bile acids: reference values in healthy dogs and comparison of two kit methods.

Serum bile acid (SBA) reference intervals were established by use of a radioimmunoassay method for fasting dogs to be 0.2 to 4.3 micro mol/L (n = 60) and for 2 hour postprandial samples to be 0.6 to 24.2 micro mol/L (n = 37). The SBA reference intervals estimated using an enzymatic method were 0 to 8.6 micro mol/L for fasting (n = 26) and 0 to 29.8 micro mol/L for 2 hour postprandial samples (n = 36). The correlation between the two methods including samples from healthy dogs and clinical cases is good (n = 128, r = 0.82, p < 0.0001). The radioimmunoassay method is linear to 50 micro mol/L and the enzymatic method is linear to 100 micro mol/L, thus both methods require serum dilutions to be made in many cases of primary liver disease. The enzymatic method is less expensive and more convenient for use in a clinical laboratory but requires a greater sample volume (400 micro I) than the RIA method (50 micro I). Both methods have adequate precision and accuracy to be useful as diagnostic tests of liver function in dogs.

Journal Article↗
PubMedDate not supplied

[The OCRA method: updating of reference values and prediction models of occurrence of work-related musculo-skeletal diseases of the upper limbs (UL-WMSDs) in working populations exposed to repetitive movements and exertions of the upper limbs].

BACKGROUND: The paper considers a database of old (already published) and new data concerning 23 groups of workers (Total number of subjects examined=5373) with different levels of exposure to repetitive movements of the upper limbs: for all these groups data were available regarding exposure indexes (OCRA index and Checklist "OCRA" score) and clinically determined UL-WMSD outcomes (PA=Prevalence of workers Affected by one or more UL- WMSDs; PC=Prevalence of single diagnosed Cases of an UL- WMSDs). OBJECTIVES: Using these data, the paper aimed at presenting and discussing the results obtained in order to estimate: new critical values of OCRA index for discriminating different exposure levels (green, yellow, red areas); new prediction models of expected PA and PC in exposed populations based on exposure indexes. METHODS: New critical values of the OCRA index (and, consequently, of the checklist score) were estimated by an original approach in which data of the effect variable PA in a reference population not exposed to the specific risks were combined with the regression function between OCRA and PA, as resulting from the 23 available groups. RESULTS: The resulting critical values and the consequent classification system of the OCRA index and of the checklist score are synthetically reported in the following table: [table: see text]. The best simple regression functions between exposure indexes (OCRA; checklist) and health outcome variables (PA; PC) were then sought, in order to obtain prediction models of effects starting from exposure. The following were the main prediction models derived from the available set of data (standard error of b in brackets): [formula: see text]. Finally, a multiple regression model was computed for estimating PA (Y) based on OCRA index and gender structure of the group (SEXRATIO=n. females x 100/n. total) with its 5 degrees and 95 degrees percentiles (in brackets); the resulting model was. Y = 2.02 (1.72-2.32) x OCRA + 0.075 (0.035-0.115) x SEXRATIO. This model showed a very high association between the two independent variables and the effect variable (PA) (R2=0.96). DISCUSSION: Discussion of the results obtained considers their intrinsic limits, as they are based on prevalence studies, and also suggests due recommendations and caution in the use of the proposed classification system and prediction models when the OCRA methods are applied for the evaluation of occupational risk associated with repetitive movements of the upper limbs.

Adolescent↗
PubMed1994

[Reference values of lipoprotein(a) in a French population].

OBJECTIVES: The aim of this work is to study the effect of different biological factors that could affect Lp(a) level in a presumably healthy population and to establish reference limits. METHODS: We selected 723 subjects (367 men and 356 women) for the age interval 4 to 64 years for evaluation. RESULTS: The distribution of Lp(a) is not Gaussian; 50.5% of subjects had Lp(a) concentrations under 0.10 g/l and the value for the 75th percentile was 0.27 g/l and 0.57 g/l for the 90th percentile. No relationship was observed between Lp(a) concentration and cholesterolaemia, triglyceridaemia, glycaemia, inflammatory proteins (orosomucoide and CRP), overweight, tobacco consumption and oral contraceptive use. The menopause state in women was a factor correlated with increased Lp(a) but this increase was not significant. Moreover, alcohol consumption (more than 44 g per day in men and more than 22 g per day in women) was associated with lower Lp(a) values. Among familial cardiovascular risks, only paternal listing of hypertension was associated with Lp(a) concentration in men. CONCLUSION: The measurement of Lp(a) in a young subject could be used as a genetic marker of cardiovascular risk associated with abnormal lipid metabolism and thrombosis phenomena.

Adolescent↗
PubMed1994

[Measuring fibrinogen concentrations in healthy dogs: standardization, comparison of methods and reference values].

Plasma fibrinogen concentration was measured in 67 healthy, adult dogs using five different methods (gravimetry, methods described by JACOBSSON (1955) RATNOFF and MENZIE (1951), and CLAUSS (1957), and functional photometric assay). Apart from using linear regression and the Pearson correlation coefficient (r) in order to characterize the relation between different methods, reference ranges (2.5-97.5%-fractile) were calculated for all methods. For calibration of the CLAUSS method (1957) and the photometric assay, dog plasma with a defined fibrinogen concentration was used. Measurements of commercial human fibrinogen standards yielded a good conformity with the concentrations specified by the manufacturer (values approximately 3% too low). These standards appear, therefore, to be also suited to the calibration of measurements of dog fibrinogen. The reference range for the gravimetry was 1.08-2.88 g fibrinogen per litre of plasma. A considerable conformity and close correlation was seen between the fibrinogen concentration measured by gravimetry and by using methods described by JACOBSSON (1955; y = 1.088 x -0.142, r = 0.967) or CLAUSS (1957; y = 0.999 x -0.004, r = 0.973), respectively. Between the reference-method gravimetry and the photometric method and RATNOFF-MENZIE (1951) method, respectively, a less close correlation, as well as a minor conformity, was found.

Animals↗
PubMed2003

[Population-based reference values for the Spanish version of the SF-36 Health Survey in the elderly].

BACKGROUND AND OBJECTIVE: The SF-36 Health Survey questionnaire is the most widely used instrument to measure health-related quality of life. Reference measures are needed to interpret its results in clinical and population studies. In 1996, a study provided population-based norms for Spain, but these were not disaggregated by age in subjects aged 75 years and over, even though health status changes with aging among those who overpass such age. Moreover, health status in elderly people from developed countries has improved over the last years. This study obtains population-based norms for the Spanish version of the SF-36 Health Survey in five-year age-groups for those aged 60 to 85 and over. SUBJECTS AND METHOD: Cross-sectional survey on a sample of 3,949 non-institutionalised subjects representative of the Spanish population aged 60 years and over. Information on the SF-36 Health Survey was obtained through house-hold personal interviews. Central position and dispersion statistics, as well as percentiles, were calculated for each of the eight SF-36 scales by age and sex. Cronbach's alpha coefficients were calculated to assess the internal reliability of each scale. RESULTS: Subjects reported higher scores for emotional role (mean [SD] 84.8 [32.9]), social functioning (79.2 [28.0]) and physical role (73.3 [41.1]). For all scales, mean scores were higher (better perceived health) among men than women (p < 0.0001). As age increased, mean scores in all scales decreased (p for linear trend < 0.001) except for mental health (p for linear trend = 0.29 in women, p for lineal trend = 0.14 in men), yet the decrease was greater for physical functioning and physical role. Reliability was very high for all scales (Cronbach's alpha from 0.84 to 0.95). RESULTS were similar to those of the study carried out in 1996. CONCLUSIONS: These results extend those obtained in 1996 and facilitate the interpretation of the SF-36 Health Survey values in clinical and population studies in the Spanish population aged 60 years and older.

Aged↗
PubMed1988

Reference values for analytes of 24-h urine collections known to be complete.

One hundred and twenty two 24-h urine collections were obtained from a representative sample of men and women in the general population aged 25-44 years. The collections were verified for their completeness by urine recovery of oral doses of para-amino benzoic acid. Means (with 0.95 reference intervals) for both sexes for 24-h urinary output were determined for nitrogen, urea, creatinine, urate, ammonia, sodium, potassium, volume, and pH. Within person variation in nitrogen, urea, creatinine, ammonia, sodium and potassium was estimated for a consecutive 28-day series of 24-h urine collections for eight individuals. Within person variation was greatest for sodium and least for creatinine. These differences when compared with the between person variation in the analytes studied have implications for the precision with which a result from a single specimen can be used to place an individual within a distribution of values for epidemiological purposes. In clinical biochemistry, the population results reported here should be appropriate as a reference base for comparison with individual patient results.

4-Aminobenzoic Acid↗
PubMed1985

Variable distributions of serum creatine kinase reference values. Relationship to exercise activity.

Although the effect of exercise on serum creatine kinase (CK: EC 2.7.3.2) activity is well known, no standard protocol for blood collection conditions has been developed. Variable frequency distributions of CK activities have been reported for reference range samples from different laboratories and have been attributed to laboratory differences. In this study the frequency distributions of creatine kinase activities (CK: EC 2.7.3.2) in serum samples obtained from the same groups of volunteers varied from a normal Gaussian distribution, to skewed distributions, on different occasions. In one collection extremely high CK values followed the performance of an eccentric exercise step test 5-8 days previously. In 2 students serum CK activities had not returned to resting values 12 and 15 days later. Peak serum CK values occurred within 24 h of other types of exercise. Serum CK frequency distributions in blood samples obtained from a group of nurses was skewed, whereas the distribution in mothers of school children was Gaussian. When repeat samples were obtained from the nurses after instruction to avoid exercise, the distribution became Gaussian. In view of the increasing levels of physical activity in the community, a standard protocol for serum CK analysis is required, in which exercise activity over the previous three weeks should be documented. Test subjects should be counselled to avoid unusual eccentric exercise and sampling should include 3 tests at least 1 week apart.

Adolescent↗
PubMed1990

Transcranial pulsed Doppler measurements of blood flow velocity in the middle cerebral artery: reference values at rest and during hyperventilation in healthy children and adolescents in relation to age and sex.

Transcranial pulsed Doppler (TCD) measurement of blood flow velocity in the middle cerebral artery was performed in 76 healthy children and adolescents (age 2-19 years), to obtain normative reference data, both at rest and during hyperventilation (from 10 years on). The Mean Flow Velocity (MFV) decreased with increasing age. Girls of 10 years or older showed a tendency for higher MFV values than boys of the same age. In combination with a previous study, this suggests that females in their reproductive years have higher maximal MFV values than males. The MFV values, during hyperventilation, were higher in girls than in boys. This gender difference, as in adults, disappeared gradually at lower levels of pCO2. At the lowest pCO2 levels, systolic minus diastolic blood flow velocity was more sensitive to vascular changes than MFV. With TCD measurements, age, sex, and pCO2 have to be taken into account, for a correct interpretation of the data obtained.

Adolescent↗
PubMed2004

Reference values for insulin-like growth factor-binding protein-3 (IGFBP-3) and the ratio of insulin-like growth factor-I to IGFBP-3 throughout childhood and adolescence.

To facilitate the diagnosis of GH deficiency and monitor GH therapy, we constructed two reference models to allow comparison of serum IGF binding protein (IGFBP)-3 concentrations and IGF-I to IGFBP-3 ratios among children throughout childhood and adolescence. This report presents equations for determining the sd score of IGFBP-3 and IGF-I to IGFBP-3 measurements for individual patients. The data set contains serum values from 468 healthy children and adolescents (232 males, 236 females; ages 1.1-18.3 yr) whose height, weight, and body mass index were within +/- 3 sd of means. Puberty was classified according to breast development (B) and testicular volume into pre-, early, mid-, and late puberty. The values of IGFBP-3 and IGF-I to IGFBP-3 ratios were log transformed, and multiple linear regression analysis was used to identify models for converting serum concentrations into sd scores. The models include the variables of age, gender, and puberty and take into account the interactions among these variables. The best linear models explain 42% of the variation in serum IGFBP-3 concentrations and 50% of the variation in serum IGF-I to IGFBP-3 concentrations. The relationship between age and log(IGFBP-3) was positive for boys in pre-, early, and midpuberty. In late puberty, values were higher than earlier in puberty, and there was a negative relationship with age. For girls the relationship between age and log(IGFBP-3) also was positive in pre- and early puberty, with larger effect for girls older than 8 yr. Values for girls in midpuberty were relatively constant, and in late puberty values were higher than earlier in puberty, and there was a negative relationship with age. The relationship between age and log(IGF-I to IGFBP-3 ratio) was positive for boys in pre-, early, and early midpuberty (volume = 9-14 ml). In late midpuberty (volume = 15-19 ml), the relationship between age and IGF-I to IGFBP-3 ratio was negative. In late puberty, values were relatively constant and higher than earlier in puberty. For girls in prepuberty, the relationship with age was positive, with a larger effect in girls older than 8 yr. In early puberty, the girls' values were relatively constant. In early midpuberty (B = 3), log(IGF-I to IGFBP-3 ratio) values were higher for girls than boys of the same age. In late midpuberty (B = 4), the relationship with age was negative, and in late puberty values were relatively constant and higher than earlier in puberty.

Adolescent↗
PubMed1993

Spirometry reference values for women and men 65 to 85 years of age. Cardiovascular health study.

Pulmonary function was assessed by spirometry in 5,201 ambulatory elderly participants of the Cardiovascular Health Study, sampled from four communities. A stringent quality assurance program exceeded American Thoracic Society (ATS) recommendations for spirometry. Less than 6% of the participants were unable to perform three acceptable spirometry maneuvers. A "healthy" subgroup of 777 women and men 65 to 85 yr of age was identified by excluding smokers and those with lung disease and other factors determined to independently, significantly, and negatively influence the FEV1. Results from black participants were examined separately. Reference equations and normal ranges for FEV1, FVC, and the FEV1/FVC ratio were determined from the healthy group. The results demonstrate differences in predicted values as great as 20% (0.5 to 1 L) for elderly patients when compared with the spirometry reference equations that are most commonly used in the United States.

Aged↗
PubMed1993

Reference values and participant means as targets in proficiency testing.

Regulatory agencies will be placing greater reliance on the results of proficiency testing (PT) for determining licensing status of individual laboratories. This has caused a renewed interest in the process used by proficiency test providers for determining the correct result for each proficiency test challenge. Three general techniques have been proposed and would be allowed under the regulations: (1) participant-derived targets (means from a specific group of participants); (2) targets from a set of "reference" laboratories, from either a subset of participants or a selected group of experts using a rigorous experimental protocol; or (3) definitive values from a single source. The College of American Pathologists (CAP) has used all three techniques at different stages and for different purposes in the history of the CAP Surveys programs. This article reviews the early experiences of the CAP, the evolution of the current protocol, and activities to monitor the accuracy of target values. Participant-derived "consensus" results have been shown to be highly accurate and reliable. The CAP uses definitive methods at the National Institute for Standards and Technology and certified reference materials to monitor the validity of targets used in proficiency testing.

Humans↗