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PubMed2005

Impulse oscillometry: reference values in children 100 to 150 cm in height and 3 to 10 years of age.

OBJECTIVES: To generate reference equations in North American children to be used for assessing respiratory function through the forced oscillation (Rfo) technique, and to determine the changes in oscillatory resistance, reactance, and resonant frequency (Fres) in relation to age, body height, and weight. DESIGN/SETTING: A prospective cross-sectional study performed on healthy children selected according to strict criteria of American Thoracic Society and European Respiratory Society recommendations. MEASUREMENTS: Triplicate measures were obtained of resistance and reactance at 5, 10, 15, 20, 25, and 35 Hz as well as Fres through the impulse oscillometer (MasterScreen IOS; Jaeger/Toennies; Höchberg, Germany). Two hundred twenty-two white children--normally distributed within the 3- to 10-year age range and 100 to 150 cm in height--were recruited in Montreal, Canada. We used regression analysis to generate multiple predictive equations separately per gender and frequency on age, height, and body weight. RESULTS: Stepwise multiple regression in both natural and logarithmic forms for height, weight, age, and gender showed that standing height was the only significant predictor for all variables. Minimal variability was noted in each subject among the triplicate measurements (p = 0.68 to 0.96). Coherence was > 0.9 at all oscillating frequencies except 5 Hz (< 0.72), with tendencies to lower values in young children. CONCLUSIONS: Resistance and Fres decrease by height, but also by age; and reactance increases. As opposed to our past experience with spirometry in compatible age groups, the Rfo technique was well accepted by preschool children.

Body Height↗

PubMed1979

Sex and age correlated reference values of serum thyroglobulin measured by a modified radioimmunoassay.

The aim of the present investigation was to describe variations in serum thyroglobulin in relation to sex and age in a group of normal persons. The method used was a modified double antibody radioimmunoassay characterized by pre-incubation at 37 degrees C of standard or sample with antiserum, resulting in a reduced total incubation time. Both sensitivity and precision were comparable to other published methods. Of the 152 blood-donors initially investigated, 7 were excluded due to the presence of antithyroglobulin antibodies as evidenced by a radioassay. Both sexes were equally represented with an even distribution of ages from 20-65 years. Increased serum thyroglobulin with increasing age was demonstrated, the correlation being significant in women (Kendall's tau, P less than 0.001). Detectable concentrations of serum thyroglobulin (above 1.7 microgram/1) were found in 94%. Based on the logarithmic transformation, the upper reference limits were determined for men less than or equal to 40 years: 36 microgram/l, greater than 40 years: 44 microgram/l (difference between groups not significant, P greater than 0.05), and for women less than or equal to 40 years: 30 microgram/l, greater than 40 years: 60 microgram/l (significant difference, P less than 0.005).

Adult↗

PubMed2001

[Determination by flow cytometry of reference values of erythrocyte parameters in aged subjects].

OBJECTIVES: Normal values for hemoglobin and hematocrit have been established for healthy young adults, but it is unknown whether age-related decline in hematological values occurs in the elderly. We compared normal values of hematological parameters in healthy adults and healthy persons aged 65 years and over using flow cytometry. SUBJECTS AND METHODS: Erythrocyte and reticulocyte parameters were determined in 585 subjects (294 men and 206 women aged 26 to 64 years, and 37 men and 48 women aged 65 years and over), living independently and without medication, symptom and disease, using Technicon H1 (Bayer) and R2000 (Roche) analyzers. Serum erythropoietin levels, red cell folate and creatinine clearance were determined in subjects aged 65 years and over. RESULTS: Irrespective of subject age, hemoglobin (Hb), hematocrit (Hct), red blood cell count (RBC), mean cell volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were higher in males than in females, but sex-related differences tended to decrease with aging. In males, there was a trend toward lower Hb and Hct with aging, due to an increase in RBC, MCV and MCH. In females, Hb and Hct (p < 0.05) increased with aging, due to a trend toward higher values of RBC, MCV and MCH. Red blood cell distribution width and hemoglobin distribution width were not modified by aging. Despite these age-related changes in erythrocyte parameters, values for anemia defined in adults appear appropriate for geriatric subjects (Hb < 130 g/l in males and Hb < 120 g/l in females). Reticulocyte count and creatinine clearance decreased in men and women aged 65 years and over (p < 0.05), whereas erythropoietin levels and red cell folate were not influenced by aging. CONCLUSION: Normal erythrocyte values defined in adults are appropriate for evaluating hematological test results in older individuals. The decrease in reticulocyte count observed in men and women aged 65 years and over does not appear to be linked to a decrease in erythropoietin production with aging.

Adult↗

PubMedDate not supplied

Reference values for singleton and twin placental weights.

The largest series of normal singleton placental weights was collected in the Collaborative Perinatal Study between the years 1959 and 1966 but values for normal twin placental weights were not published. In our study we examined 787 singleton and 514 twin normal placentas. Placentas with associated conditions known to affect the weights of placentas were excluded. After establishing the normal values for singleton and twin placental weights, we concluded that weight gain of twin placentas appears to accelerate between 24 and 36 weeks but reaches a plateau after 37 weeks, whereas singleton placentas appear to gain weight more uniformly throughout gestation. The mean values of twin placental weights for each gestational age are less than double those of singleton placental weights for the same duration of gestation. Our singleton and twin placentas are heavier than those from previously published data and may reflect a generational or nutritional change over the 30 years since the original numbers were compiled.

Humans↗

PubMed1988

Urinary thallium: critical problems, reference values and preliminary results of an investigation in workers with suspected industrial exposure.

Using a sensitive ETA ASS method, urinary thallium (Tl-U) has been measured in a group of non-exposed individuals and in two groups of workers with suspected industrial exposure. In non-exposed subjects (72 healthy males aged 41 +/- 11 years) the Tl-U mean value was 0.22 mu/l (range 0.05-0.61). Significantly higher values were found in two groups of workers (30 and 21 subjects) employed in two cement factories and two cast iron foundries (mean Tl-U value: 0.38 and 0.33 mu/l, respectively; range 0.06-1.2). Thallium has been determined in coal, raw materials and, in one factory, also in environmental samples, but no detectable levels were found. The analytical problems connected to urinary thallium determination and the preliminary results of biological monitoring in non-exposed individuals and in workers are discussed.

Environmental Exposure↗

PubMed1982

Metabolic profile testing for Jersey cows in Louisiana: reference values.

One hundred twenty-seven Jersey cows (1 to 6 years of age) within a 160.93-km radius of Baton Rouge, La, were selected at random over a 3-year period to determine serum values for total creatine kinase, aspartate transaminase, calcium, phosphorus, alkaline phosphatase, cholesterol, total protein, globulin, urea nitrogen, and glucose. Breed and age were partitioned as possible sources of variation. Seasonal temperature and management influences were taken into account by restricting the sampling area. Seasonal temperature and management influences along with reproductive status and stage of lactation, were randomized by sampling over the 3-year period. All serum values, except aspartate transaminase, urea nitrogen, and glucose were influenced by age. Serum cholesterol, total protein, and glucose were influenced by age. serum cholesterol, total protein, and globulin tended to increase with age, whereas creatine kinase, calcium, phosphorus, and alkaline phosphatase generally decreased with age.

Age Factors↗

PubMed1982

Sensory nerve conduction velocity of cutaneous afferents of the radial, ulnar, peroneal, and tibial nerves of the dog: reference values.

The mean conduction velocities of the compound action potentials of sensory axons of the cutaneous branches of the radial, ulnar, peroneal, and tibial nerves of the healthy dog were determined by cutaneous stimulation and recorded by averaged evoked response technique. Locations for both stimulation and recording electrodes were identified. Mean conduction velocities were: radial nerve = 65.1 +/- 6.2; ulnar nerve = 69.4 +/- 6.9; peroneal nerve = 64.4 +/- 5.25; and tibial nerve = 63.4 +/- 5.3 m/s +/- SD.

Action Potentials↗

PubMed1991

[Reference values for quantitative image analysis of indocyanine green video-fluorescence angiography].

Indocyanine green video-fluorescence angiography was performed in 46 healthy normal subjects between the ages of 20 and 81 years using a 30 degrees Zeiss fundus camera, an external light supply and a high resolution CCD camera. Pictures were directly stored in a picture analysis system based on a PC with a temporal resolution of 25 pictures per second. Using statistical picture analysis, choroidal blood-flow parameters were obtained in a round area of interest with a diameter of 8 degrees with the center in the fovea. The parameters include: the mean arterial filling time (AFT) and the mean capillary density (MCD) in the choroid. There was no correlation for one of these parameters with arterial blood pressure or intraocular pressure. All values for the AFT were on an equal level for normal subjects younger than 65 years. Older normal subjects in some cases had clearly increased arterial filling times. The density of the capillary network in the choroid was significantly reduced with increasing age, and there was reduced density of the capillary network in normals with myopia.

Adult↗

PubMed1989

Myocardial 201Tl washout after combined dipyridamole submaximal exercise stress: reference values from different patient groups.

Dipyridamole stress is favorable in patients unable to exercise maximally for 201Tl myocardial scintigraphy. Aside from an analysis of uptake defects, proper washout analysis can be limited by heart rate variations when isolated dipyridamole stress is used. Heart rate standardized 201Tl washout kinetics after a combined dipyridamole and submaximal exercise stress protocol (CDSE), feasible in elderly patients as well as in patients with peripheral artery disease, were therefore studied to investigate the 201Tl washout after CDSE in differently defined patient groups: Group I comprised 19 patients with documented heart disease and angiographically excluded coronary artery disease (CAD); group II contained 17 patients with a very low likelihood of CAD determined by both normal exercise radionuclide ventriculography and normal 201Tl uptake. Group III comprised 56 patients with a 50% pretest likelihood of CAD but normal 201Tl uptake. Mean washout values were nearly identical in all groups. Despite similar uptake patterns, however, washout standardized by CDSE was significantly lower than the normal washout values after maximal treadmill exercise. Thus an obviously lower 201Tl washout after CDSE than after maximal treadmill exercise must be considered if washout analysis criteria after dipyridamole are applied to evaluate ischemic heart disease. Nevertheless, heart rate elevation achieved by additional submaximal exercise stress seems necessary, adequate and clinically safe for standardisation of washout analysis in dipyridamole 201Tl scintigraphy.

Adult↗

PubMedDate not supplied

[Reference values of the red blood profile in beagle, German shepherd and golden retriever puppies].

In the present study, blood samples were taken from clinically healthy puppies of the breeds Beagle, German Shepherd, and Golden Retriever between days 1 and 3 (n = 146), 8 and 10 (n = 137), 28 and 33 (n = 151), and 50 and 58 (n = 129) post natum. Measurements for red blood cell count, haemoglobin concentration, haematocrit, mean erythrocyte volume (MCV), mean corpuscular haemoglobin (MCH), and mean corpuscular haemoglobin concentration (MCHC) were performed by a semi-automatic blood cell counter; the normoblast number was counted visually. Between the 1st and 3rd day of life, the erythrocyte number of the puppies was 4.57 +/- 0.68 10(6)/microliter and, as such, was clearly below the reference range for adult animals. It further decreased by the 2nd measurement (8th to 10th day of life) to 3.59 +/- 0.41 10(6)/microliter, and then increased again to 4.75 +/- 0.68 10(6)/microliter (reference range: 3.73-6.25 10(6)/microliter, 2.5% to 97.5% percentile) by the final measurement (50th to 58th day of life). The measurement values of the haemoglobin concentration (13.5 +/- 2.0 g/dl) and haematocrit (41.0 +/- 6.5%) after birth were only insignificantly below or around the lower limit of the reference range for adult animals. Both parameters decreased to a more pronounced extent than did the erythrocyte count. They reached a minimum of 8.4 +/- 1.0 g/dl and 26.8 +/- 3.2%, respectively, between the 28th and 33rd day of life. Even at the end of the examination period (50th to 58th day of life), the values of these parameters (10.1 +/- 1.1 g/dl, reference range: 7.5-11.8 g/dl; 32.1 +/- 4.2%, reference range: 24.8 to 40.8%) were remarkably lower than the minimum of reference range for adult dogs. At the 1st sampling (between 1st and 3rd day of life), MCV (89.8 +/- 6.7 fl) and MCH (29.6 +/- 1.9 pg) were distinctly higher than the reference values for adult dogs. Both parameters decreased with increasing age. Thus, from the 50th-58th day of life, the results were comparable to those of adults. No considerable age dependence was found for MCHC. During the first days of life a relatively high number of normoblasts (8 +/- 7/100 Leukozyten) was found; it decreased rapidly. The study revealed significant differences between the breeds, e.g. German Shepherd dogs had lower initial values of erythrocyte count, haemoglobin concentration, and haematocrit when compared to the other breeds. Puppies of this breed also had higher normoblast numbers than the Beagle and Golden Retriever puppies at the 2nd and 3rd samplings. No clear sex differences in the studied parameters were observed. The results of this study reflect the replacement of fetal erythrocytes by postnatal erythrocytes. Moreover, they illustrate the need to use age as well as breed-specific reference ranges.

Aging↗

PubMed1989

[Normal and borderline ambulatory arterial pressures. A new method for establishing reference values].

Ambulatory arterial pressures, both systolic (SAP) and diastolic (DAP), together with heart rate were measured every 15 minutes during 24 hours, using a Spacelabs 5200 apparatus, in 168 male subjects of mean age 21 +/- 1 years. According to the WHO criteria, 72 subjects had normal arterial pressure (clinical DAP less than or equal to 90 mmHg, clinical SAP less than or equal to 140 mmHg), and 86 subjects had untreated borderline arterial hypertension (abnormal clinical pressures, with clinical DAP less than or equal to 95 mmHg and clinical SAP less than or equal to 160 mmHg). On the basis of the WHO criteria, a sizeable part of pressure profiles in the normal and hypertensive groups overlapped. The Mc Queen method, derived from cluster analysis, considerably reduces this overlap. The method defines and objective criterion which enables the subjects to be reclassified in cases where clinical and ambulatory pressures "contradict each other". Such reclassification applied in about 20% of our subjects. This leads to a new definition of reference groups based on both clinical pressure and ambulatory pressure profile. The WHO criteria remain the basis for this classification. The Mc Queen method may be used to define normal and borderline arterial pressure profiles in male and female subjects of different age-groups.

Adult↗

PubMedDate not supplied

Chronobiologic reference values in clinical chemistry.

Circadian rhythms of 23 biochemical parameters were studied in the serum of 194 children 11 +/- 1.5 years of age, 43 young adult subjects 21 +/- 2 years of age and 200 elderly subjects 77 +/- 8 years of age. In the children and the elderly subjects, the investigations extended over all four seasons allowing also the study of seasonal variations or circannual rhythms. The circadian rhythms were characterized by population mean cosinor for each group and sex. The circannual rhythms were explored by single cosinor and one and two way analysis of variance applied to the circadian means obtained during each season, and by the comparison of the circadian rhythm parameters obtained during the four seasons by the parameter test described by Bingham et al. Circadian rhythms were found in most and circannual rhythms in many parameters. The rhythm characteristics are presented as cosinor summaries. A number of laboratory parameters show high amplitude rhythms in one or the other frequency studies and require time-qualified reference ranges for a meaningful use of these variables for clinical diagnosis. The majority shows small amplitude rhythms, which do not pose diagnostic problems, but are indicators of the complex time structure of the human organism.

Adult↗

PubMed1984

Sensory nerve conduction velocity of cutaneous afferents of the radial, ulnar, peroneal, and tibial nerves of the cat: reference values.

The mean conduction velocities of the compound action potentials of sensory axons of the cutaneous branches of the radial, ulnar, peroneal, and tibial nerves of the healthy cat were determined by cutaneous stimulation and recorded by averaged evoked response technique. Locations for both stimulation and recording electrodes were identified. Mean conduction velocities were: radial nerve, 83.6 +/- SD 8.3; ulnar nerve, 89.2 +/- 10.3; peroneal nerve, 85.3 +/- 6.8; and tibial nerve, 80.2 +/- 7.9 m/s.

Afferent Pathways↗

PubMedDate not supplied

Reference values for radial bone width and mineral content using single photon absorptiometry in healthy children aged 4 to 10 years.

Bone width and mineral content were measured in 420 healthy Cambridge children aged 4 to 10 years using single photon absorptiometry. The results are expressed first in the form of standard centile charts, with additional prediction charts which provide body-size-adjusted estimates for the measurements, and interpretation centiles for comparing these estimates with the actual measurements. The values obtained are similar to those reported for American children aged five to six years after adjusting for body-size differences. We suggest that appropriate application of these prediction charts will facilitate the use of single photon absorptiometry in monitoring and treating children who have disorders of bone growth and mineralization.

Absorptiometry, Photon↗

PubMed1994

Haematology and biochemistry reference values for sows kept under modern management conditions.

The data presented here were obtained using blood samples from 159 healthy, conventionally managed sows from 37 breeding herds. Sows were sampled at weaning and at 4-5 weeks gestation. Paired blood samples were analysed from sows that had a normal pregnancy and subsequently farrowed. The mean values of serum total protein, albumin and gamma globulin concentration were lower in the blood samples obtained at weaning compared with those obtained at 4-5 weeks gestation. Leucocyte count was higher, mostly as a result of a higher segmented neutrophil count, in the blood samples obtained at weaning compared with those obtained at 4-5 weeks gestation.

Animal Husbandry↗

PubMed1985

[Concentrations of free and bound 4-aminobutyric acid in human serum: reference values].

A rapid and sensitive procedure is described for the quantification of gamma-aminobutyric acid in human plasma, using ion-exchange fluorescence. Analytical values for gamma-aminobutyric acid vary according to the method of deproteinization, storage conditions and sample treatment. A practicable and precise method for the evaluation of free and bound gamma-aminobutyric acid is presented. The mean concentration of the free neurotransmitter in neurologically normal control subjects was 142.4 +/- 13.1 nmol/l (n = 30). The mean concentration of the bound form was 438.6 +/- 51.1 nmol/l in the same subgroup.

Adolescent↗

PubMed1997

A new, fast and reliable radioimmunoassay of brain natriuretic peptide in human plasma. Reference values in healthy subjects and in patients with different diseases.

A new, fast and reliable radioimmunoassay for measurement of brain natriuretic peptide (BNP) in human plasma has been developed and its application is reported in healthy subjects and in patients with congestive heart failure, chronic renal failure, liver cirrhosis and essential hypertension. The antibody was raised in rabbits, the tracer was made by the iodogen method and polyethylene glycol was used for separation of free and bound tracer. BNP was extracted from plasma using Sep-Pak C18 cartridges. The recovery of unlabelled BNP added to plasma was 77.5 +/- 6.2% (mean +/- SD). The detection limit in plasma was 0.55 pmol l-1. No cross-reactivity existed with the natriuretic peptides ANP, CNP or urodilatin. In 124 healthy subjects the mean BNP was 1.8 +/- 1.0 pmol l-1 (SD), range 0.6-5.5. BNP increased slightly with age, was higher in women than men and had no circadian rhythm. In eight patients with congestive heart failure the median BNP level was 30.5 pmol l-1, range 3.9-65.3. In 14 patients with chronic renal failure the median BNP level was 50.5 pmol l-1, range 10.9-219.8 before dialysis, and 38.0 pmol l-1, range 9.4-180.0 immediately following dialysis. In 25 patients with liver cirrhosis the median BNP value was 7.8 pmol l-1, range 1.2-43.1. There was no difference between patients with or without ascites. In 18 medically treated patients with essential hypertension the median BNP level was 5.0 pmol l-1, range 1.2-45.5 pmol l-1.

Adult↗

PubMedDate not supplied

Spirometric response to a bronchodilator. Reference values for healthy children and adolescents.

The spirometric response to inhaled salbutamol was assessed in 492 healthy volunteers 6 to 20 yr of age. Mean and standard deviation of the changes, expressed as percentage of prebronchodilator values, were as follows: forced vital capacity (FVC): 1.7 +/- 2.8; forced expiratory volume in one second (FEV1): 3.3 +/- 3.4; (FEV1/FVC): 3.1 +/- 3.2; peak expiratory flow: 6.4 +/- 8.6; maximal mid-expiratory flow: 10.1 +/- 8.8; maximum expiratory flow at 50% of FVC: 8.8 +/- 9.5 and maximum expiratory flow at 25% of FVC: 14.0 +/- 14.7. The changes were significant (p less than 0.005) for all parameters and similar to those observed in adults.

Adolescent↗