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PubMed1988

Reference values for FEV1 in Japanese-American men from 45 to 68 years of age.

Pulmonary function is known to vary by racial group, yet no standards have been published for Asian-Americans. The Honolulu Heart Program, a prospective epidemiologic study of cardiovascular disease, provided an opportunity to examine pulmonary function, specifically, forced expiratory volume in one second (FEV1), in Japanese-American men 45 to 68 yr of age. Of a cohort of 6,346 men, 1,490 were identified as healthy asymptomatic nonsmokers. Prediction equations and reference values were derived from this subgroup. When the prediction equation was compared with those derived from Caucasian and black populations, mean predicted FEV1 for Japanese-Americans was intermediate to higher values for Caucasians and lower values for blacks. In addition to age and height, skinfolds, dynamometry, and biacromial diameter were found to be independent predictors of FEV1. In summary, standards derived from Japanese-American populations should be used when measuring pulmonary function in this group and additional physical measurements make a small contribution to the accuracy of prediction equations.

Aged↗

PubMed1993

[Establishment of serum lipid reference values in school-age children in Subotica].

The aim of the study was to establish the levels of specific lipid parameters in schoolchildren from Subotica. The study comprised 393 pupils aged from 7 to 14 years in whom the levels of the centile for total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were determined. Levels of the total cholesterol P75 were 4.8 mmol/l in boys and 4.85 mmol/l in girls. High risk levels of P95 were 5.55 mmol/l in boys and 5.00 mmol/l in girls. Levels of LDL cholesterol P75 were 2.91 mmol/l in boys and 2.84 mmol/l in girls. High risk levels of P95 were 3.65 mmol/l in boys and 3.60 mmol/l in girls. A level of HDL cholesterol below P10 may be considered as dangerous for boys below 1.00 mmol/l and for girls below 1.11 mmol/l. The authors are of the opinion that the results of the study will contribute to the establishment of serum lipid reference values in schoolchildren in this territory.

Adolescent↗

PubMed1996

Reference values for young normal Sprague-Dawley rats: weight gain, hematology and clinical chemistry.

1. Arterial blood from 63 male (315-500 g) and 60 female (210-290 g) healthy Sprague-Dawley rats was analyzed for 16 hematological and 22 clinical chemistry parameters. 2. Nine of these parameters were associated with growth and developmental changes in males between 38-78 days and females 49 - 89 days of age. 3. Weight gain in both sexes followed patterns consistent with other studies using this strain, but interexperimental variation was as much as +/-22%. 4. Rectal temperatures of females averaged 37.28 degrees C, being statistically greater (P < 0.05) than the average male at 36.99 degrees C. 5. The data provide reference values for use in toxicological and other investigations.

Age Factors↗

PubMed1998

[Investigation of the Zeta reference values by Chinese-built Zetafuge and preliminary application].

We determined the Zeta sedimentation ratio (ZSR) for 326 normal subjects and 106 inpatients by Chinese-built Zetafuge. The mean ZSR for normal subjces was 52.5 +/- 5.05% and that for inpatients 68.52 +/- 5.54% (P < 0.001). ZSR can be determined by using directly the blood sample with the anticoagulant EDTA-K2; the determination is faster and requires less volume of blood sample; it is not affected by anemia and need not be corrected for age and sex. The results of ZSR are expressed in a new unit, %, not in mm/h. The reference value we established is: < or = 62%. We also discussed the problem of reproducibility, the speed of centrifuge, the height of blood, and compared this method with the westergren method. The agreement between the two methods is 86.6%.

Adult↗

PubMed1980

Reference values for blood findings in relatively fit elderly persons.

In a retirement community group of 73 relatively fit elderly white persons, a cross-sectional study of 53 different blood tests was conducted. The five test categories for blood values were hematology, chemistry, thyroid function, protein electrophoresis, and immunology. Fifteen percent of the blood findings were outside the range accepted as normal by the examining laboratories. Most of the subjects showed between 5 and 10 "abnormal" values within the five test categories. Since the findings were fairly predictable in view of the patho-anatomic changes that accompany aging, and since the manifestations of disease were at most subclinical, only minor alterations in individual management were needed. Subsequent appropriate clinical re-evaluation of these subjects during a six-month follow-up revealed no striking changes. It would appear that the ranges of "normal" reference values may need to be expanded. Although cross-sectional laboratory studies are useful, longitudinal studies seem essential if clinicians are to attain a more valid perspective.

Aged↗

PubMed1995

Standardization of glycohemoglobin results and reference values in whole blood studied in 103 laboratories using 20 methods.

We investigated the effect of calibration with lyophilized calibrators on whole-blood glycohemoglobin (glyHb) results. One hundred three laboratories, using 20 different methods, determined glyHb in two lyophilized calibrators and two whole-blood samples. For whole-blood samples with low (5%) and high (9%) glyHb percentages, respectively, calibration decreased overall interlaboratory variation (CV) from 16% to 9% and from 11% to 6% and decreased intermethod variation from 14% to 6% and from 12% to 5%. Forty-seven laboratories, using 14 different methods, determined mean glyHb percentages in self-selected groups of 10 nondiabetic volunteers each. With calibration their overall mean (2SD) was 5.0% (0.5%), very close to the 5.0% (0.3%) derived from the reference method used in the Diabetes Control and Complications Trial. In both experiments the Abbott IMx and Vision showed deviating results. We conclude that, irrespective of the analytical method used, calibration enables standardization of glyHb results, reference values, and interpretation criteria.

Calibration↗

PubMed1986

Japanese-American pulmonary reference values: influence of environment on anthropology and physiology.

Anthropometric measurements and pulmonary function (volumes, flows, and flow-volume curves) were evaluated in a community study of 59 male and 59 female, nonsmoking, healthy Japanese-American volunteers uniformly distributed in decades from 20 to 80 years. A control group of 36 Caucasians was similarly constituted. One technologist performed all tests. Techniques and equipment matched American Thoracic Society recommendations. A cohort effect was demonstrated for anthropometric measurements in the Japanese-Americans. They were smaller and lighter than the Caucasians but taller and heavier than the Japanese of Japan. The differences from whites diminished with youth. Although the group mean volumes and flows differed little from white reference series of Crapo et al. (1981, 1982), there was a difference in the older subjects. Flow-volume curves were increased in all Japanese-Americans. Prediction equations for pulmonary function have been prepared using standing height, age, and sex. More precise formulae would need to include skinfolds, lean body weight, and span. Our Caucasians did not differ anthropometrically or in their pulmonary function from those of the mainland. In conclusion, Japanese-American anthropometry and pulmonary function in Hawaii shows a gradation from that of Japanese to Caucasians, the extent depending on the age. This is secondary to an environmental influence on anthropometry and physiology. As a consequence race-specific reference values for volumes, flows, and flow-volume curves are necessary in evaluating pulmonary function of individual Japanese-Americans.

Adult↗

PubMed2001

Reference values of amniotic fluid neuron-specific enolase.

OBJECTIVE: Enolase is a dimeric cytoplasmic enzyme whose double gamma isoenzyme, neuron-specific enolase, is predominantly found in neuronal and neuroendocrine tissues. Cell injury causes its release into the blood and cerebrospinal fluid (CSF). Neuron-specific enolase has been measured in the serum and CSF of adults and full-term asphyxiated neonates as a marker of neurological injury. We recently observed an elevation of neuron-specific enolase in the amniotic fluid of women whose neonates subsequently developed intraventricular hemorrhage or periventricular leukomalacia. The purpose of our study was to establish reference values of neuron-specific enolase in the amniotic fluid as a function of gestational age. METHODS: A total of 110 amniotic fluid samples, obtained primarily for genetic studies (16-20 weeks, n = 22), for evaluation of preterm labor (21-35 weeks, n = 66) and for fetal lung maturity studies (36-40 weeks, n = 22), were analyzed for neuron-specific enolase. Samples were from women who subsequently delivered term neonates with normal neurological examinations or who delivered preterm neonates with normal neurosonograms up to the 7th day of life. Descriptive statistics and non-parametric correlations were used for analysis. RESULTS: There was no correlation between gestational age and concentration of neuron-specific enolase (Spearman's r = 0.059, p = 0.63). The overall mean neuron-specific enolase value was 2.5 +/- 1.39 microg/l. The highest value obtained was 6 microgl. Of the 110 women, 105 (95.5%) had neuron-specific enolase values of less than 5 microg/l, while five (4.5%) had values ranging from 5 to 6 microg/l. CONCLUSIONS: The amniotic fluid level of neuron-specific enolase does not change as a function of gestational age. These stable levels may have utility in the evaluation of cases with fetal neurological injury.

Adult↗

PubMed1994

Immunoturbidimetry of serum apolipoproteins A-I and B on the Cobas Bio centrifugal analyzer: method validation and reference values.

We describe an immunoturbidimetric assay for estimating the concentration of apolipoproteins (apo) A-I and B in serum with a Cobas Bio centrifugal analyzer. Several analytical variables were studied: pH, temperature, wavelength, reaction time, sample pretreatment, antisera dilution, concentration of NaCl, phosphate buffer, and PEG 6000; a good optical response was obtained with small volumes of sample and antisera. Imprecision was low, with intrarun coefficient of variance (CV) from 1.1 to 2.8% and interrun CV from 1.8 to 3.2%. We demonstrated a good correlation between our method and radial immunodiffusion for apo A-I (r = 0.975) and apo B (r = 0.980). Reference values were calculated from a sample of 494 healthy subjects, and separate intervals for the ratio of apo A-I to apo B in gender and age subgroups were established.

Adult↗

PubMedDate not supplied

[Reference values in biological monitoring of occupational exposure to mutagens and carcinogens].

This work reports values of biological markers indicating mutagenic/carcinogenic risk in professionally non-exposed populations. The main confounding factors for most of these biomarkers are tobacco smoke, diet and air pollution. With the sole exception of compounds specifically present in work environments, in which determination in biological fluids of unchanged substances or their metabolites has high sensitivity and specificity (e.g., some aromatic amines), other biomarkers (urinary mutagenicity, DNA adducts and cytogenetic analyses), in order to be used properly as reference values, require ad hoc study of suitable control groups paired for the main confounding factors. Analytical determination of some protein adducts appears to be promising, due to its sensitivity and specificity.

Air Pollutants↗

PubMed2003

Biomechanical and scaling bases for frontal and side impact injury assessment reference values.

In 1983, General Motors Corporation (GM) petitioned the National Highway Traffic Safety Administration (NHTSA) to allow the use of the biofidelic Hybrid III midsize adult male dummy as an alternate test device for FMVSS 208 compliance testing of frontal impact, passive restraint systems. To support their petition, GM made public to the international automotive community the limit values that they imposed on the Hybrid III measurements, which were called Injury Assessment Reference Values (IARVs). During the past 20 years, these IARVs have been updated based on relevant biomechanical studies that have been published and scaled to provide IARVs for the Hybrid III and CRABI families of frontal impact dummies. Limit values have also been developed for the biofidelic side impact dummies, BioSID, EuroSID2 and SID-IIs. The purpose of this paper is to provide in a single document: 1) a listing of the IARVs for measurements made with the Hybrid III and CRABI families of frontal impact dummies, and for the biofidelic side impact dummies, 2) the biomechanical and/or scaling bases for these IARVs, and 3) a comparison of IARVs and regulatory compliance limits and how they affect restraint design.

Journal Article↗

PubMed1996

Reference values of neuroactive amino acids in the cerebrospinal fluid by high-performance liquid chromatography with electrochemical and fluorescence detection.

Sampling and HPLC analysis procedures for CSF amino acid determinations were evaluated. In order to increase sensitivity, a precolumn derivatization of amino acids by o-phthalaldehyde-mercaptoethanol reagent was used. By using fluorimetric and electrochemical detection in series, positive peak identification can be obtained in a single chromatographic run. It is recommended to analyze freshly collected CSF. Amino acids are stable for short periods over a wide range of temperature, but storage at -80 degrees C is recommended. The CSF samples for the calculation of the reference values were taken from 40 healthy subjects, hospitalized for lumbar disk herniation, placed on the same diet and kept drug-free for at least 1 week. The mean values (mumol/l) and the ranges (in parentheses) were: 0.27 (0.09-0.63), 0.62 (0.18-1.15), 5.32 (3.05-11.50), 6.16 (2.90-13.30), 0.16 (0.03-0.22) for aspartic acid, glutamic acid, glycine, taurine and gamma-aminobutyric acid respectively.

Adult↗

PubMed2000

Lung function reference values in Chinese children and adolescents in Hong Kong. II. Prediction equations for plethysmographic lung volumes.

As part of a comprehensive evaluation of lung function in Hong Kong Chinese children and adolescents, over a thousand healthy subjects aged 7-19 yr from seven schools were recruited for lung function testing that included spirometry and, in many cases, lung subdivision measurements. Lung function tests were performed using SensorMedics Automated Body Plethysmograph according to published standards. Of these, 551 subjects (219 males), aged 8-19 yr, had satisfactory lung subdivision indices recorded. Analysis for the values of lung subdivisions including total lung capacity (TLC), residual volume (RV), and functional residual capacity (FRC) demonstrated that standing height and sitting height were the best predictors of lung volumes. After allowing for standing height or sitting height in the regression models for lung volumes, age at examination was the second best parameter, although its inclusion into the equations contributed to less than 1% of explained variance for boys and 3% for girls. These are the first reported data in international literature on reference values for lung subdivisions in Chinese children and adolescents.

Adolescent↗

PubMed2004

The NEXUS vision: an alternative to the reference value concept.

In Lundberg's brain-to-brain turnaround time loop, the postanalytical phase is undoubtedly one of the most difficult phases. Of course, error prolongation can cause serious problems when quality is not sufficiently assessed and assured in the preanalytical and analytical phases. However, in the postanalytical phase following reporting, interpretation and action are at stake; and with this the wellbeing of the patient. Here exists a grey area of responsibility between the laboratory and physician. The laboratory should correctly report the measurement as data. But to place this in the correct context requires additional information on (specific) reference values, specificity, sensitivity and possible interpretation of the data. Here is where the ultimate interaction between the laboratory and the physician (representing the patient) occurs. What happens when errors occur in this phase? Do errors occurring in the previous phases effect this phase? What types of errors occur in the postanalytical phase? Postanalytical quality is the ultimate check on the coherence of the preanalytical, analytical and postanalytical quality; it is a check on the overall quality. It ties together the quality of the question to be answered, the analytical quality that is achieved and the usefulness of the answer obtained. In addition, it also checks quality in the context of the patient and physician interaction. Can errors be avoided and can a predictable quality level be assessed and be assured? A model, called NEXUS vision is described.

Algorithms↗

PubMed2004

Reference values for relative numbers of natural killer cells in cattle blood.

Natural killer (NK) cells have been studied in humans and rodents for almost 30 years, but little is known about NK cells in other mammals, such as cattle. Recently, a monoclonal antibody directed against bovine NKp46, a receptor that is expressed exclusively on NK cells, was developed. We have utilized this antibody to study the relative numbers of NK cells in blood of 254 cattle at different ages. The highest relative number of NK cells was observed in young calves, and gradually decreased with age to a bottom level in heifers, followed by a moderate increase in adults. Relative numbers of NK cells in cattle were generally lower than in humans, but age-related changes in bovine NK cells showed similar tendencies as reported in humans. The present material provides a source for reference values for NK cells in cattle at various ages.

Age Factors↗

PubMed2004

Assessment of left ventricular function with steady-state-free-precession magnetic resonance imaging. Reference values and a comparison to left ventriculography.

UNLABELLED: Ejection fraction (EF) and end-diastolic and end-systolic volume index (EDVI/ ESVI) derived from ventriculography are important prognostic parameters. Cine magnetic resonance imaging (MRI) using a steady-state, free-precession sequence (SSFP) offers excellent delineation of the endocardial borders and highly reproducible and accurate results for cardiac volumes. We evaluated MRI volumetry against routine x-ray ventriculography. In 200 patients EF, EDVI and ESVI were measured with MRI volumetry and x-ray ventriculography. The same MRI protocol was applied to 102 healthy persons in order to establish reference values. In healthy subjects mean EF was 68.8% +/- 5.4% (range 59-84%), mean EDVI 69 +/- 10 (43-90) and mean ESVI 22 +/- 5.8 (10-35 ml). In the patients, overall correlation (Spearman's R) of MRI with ventriculography was 0.86 for EF, 0.77 for EDVI and 0.88 for ESVI. For postextrasystolic beats (38% of the measurements), R was 0.73/0.65/0.73 for EF/EDVI/ESVI. MRI correlated best with biplane ventriculography during sinus rhythm (0.96/0.85/0.93); the worst correlation (0.78/0.81/0.83) resulted from patients with wall motion abnormalities in comparison to monoplane x-ray ventriculography. CONCLUSION: Contemporary MRI volumetry compares well to invasive data obtained under optimal conditions. In view of the known limitations of single plane ventriculography, MRI seems to allow exact volumetry independent from regional wall motion abnormalities.

Cardiac Catheterization↗

PubMedDate not supplied

Urinary lithium: distribution shape, reference values, and evaluation of exposure by inductively coupled plasma argon-emission spectrometry.

Inductively coupled plasma argon-emission spectrometry (ICPAES) was used to evaluate the lithium content of undiluted urine samples. The method can be performed with 1 mL of urine in a single tube using a routine ICPAES analysis for rapid and convenient assessment of lithium exposure in humans. Urine samples obtained from male workers (n = 86) who had not been exposed to lithium were used for the determination of this element by ICPAES. The obtained concentrations were corrected using a specific gravity of 1.024. The particular frequency distribution resulted in a log-normal distribution diagram for anatomical spread. Geometric mean value for urinary lithium in the nonexposed male workers was 23.5 microg/L, and the confidence interval from a log-normal distribution was 11.0 to 50.5 microg/L. Taking into consideration a short biological half-life and the massive urine excretion of lithium, urinary lithium was considered to be a useful index for monitoring of exposure. Calibration curves obtained for lithium standards had good sensitivity and linearity. Good reproducibility was assessed by lithium addition to urine samples. It was concluded that the obtained lithium reference values would be useful for the early diagnosis of lithium intoxication or in the assessment of the degree of exposure to lithium in subjects at risk.

Adult↗

PubMed1989

Clinical chemistry. In-clinic analysis, quality control, reference values, and system selection.

The clinician never has had a better selection of user friendly analytical systems for in-clinic use. Selection of a system should be made only after several questions have been answered, including: What is the technical knowledge and experience of the persons who will use the system? Who will initiate and supervise a quality assurance program? Which analysis and what volume of samples are anticipated now and in the future? The estimated cost per test should include the total cost of instrumentation and maintenance, calibrators, controls, reagents, and technical and supervisory time. Have the methods been validated for the animal species involved and are adequate reference values available? Read the package inserts completely for each analyte. Do not rely on the advice of salespeople for guidance in answering many of these questions, but do question them carefully about statements made, especially regarding warranties and technical service. For those clinicians willing to accept the responsibilities associated with in-clinic testing, an increased awareness of laboratory medicine and a resulting increased interest and ability to provide quality medical care can be expected.

Animals↗