PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Reference Values”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed1986

[First comprehensive spirometric studies of new reference values for unrestricted use].

In contrast to almost all other clinical data, there are as yet no uniform, generally accepted values for spirometric measurements. This is due to technical and organizational problems related to examination procedures. The numerous authors only evaluated data from certain groups of subjects. There has not yet been a uniform study of all age, socioeconomic and occupational groups, urban and rural. Organizational cooperation with a preventive--medicine field study in Styria, together with school examinations, made possible the collection of data from all necessary groups including the basic spirometric values VC, FEV1 and FEV1 %VC. Although strictest epidemiological and methodological exclusion criteria were applied, a very sufficient number of subjects in all groups resulted. All examinations were performed with a half--open dry bellows spirometer. The general validity of the data so obtained is guaranteed as by a study made for this purpose of the cooling behavior of expired air in the spirometer. This data made possible for the first time a statistically acceptable, continuous transition between the model for children and youth on the one hand, and the model for adults on the other. With this large sample, precise statements could be made on the behavior of spirometric values for the growth - period, and the relations of sex, age, height and weight defined. The resulting regression equations can be used without restriction for all relevant problems. The Austrian Standardization Commission has thus already moved to accept these values.

Adolescent↗
PubMed2005

Peak oxygen uptake. Myth and truth about an internationally accepted reference value.

This article critically examines the execution of VO(2)-peak testing in cardiac patients and questions their appropriate interpretation. In the first part, the most common clinical implications of VO(2)peak measurements are discussed: assessment of (changes in) functional capacity, evaluation of the necessity of invasive diagnostic/therapeutic measures, reference for exercise prescriptions, determination of prognosis. In the second part, important methodological problems and constraints are addressed and illustrated by references to scientific studies. Finally, recommendations are given for meaningful VO(2)peak testing. It is evident that failure to strictly follow such recommendations might result in misleading ergometric findings and, thus, in over- or underestimation of endurance capacity and/ or training effects.

Clinical Trials as Topic↗
PubMed1999

Assessment of respiratory function: influence of spirometry reference values and normality criteria selection.

The purpose of this study was to determine the impact upon classification of patients of the choice of reference equation and the criterion defining the lower limit of the normal range in clinical practice. One thousand consecutive spirometries were checked to calculate the predicted values [forced vital capacity (FVC) and forced expiratory volume in sec (FEV1)] in accordance with the equations by Morris, Cherniack, Crapo, Knudson and the Economic Community for Coal and Steel (ECCS). We quantified the difference between the predicted values obtained for each individual and each equation, determined the percentage of individuals whose classification might have changed from normal to abnormal when using a different equation and defined the lower limit of the normal range in accordance with the determination of 1. the 90% confidence interval or 2. 80% of predicted, comparing their differences. The greatest differences found were between the values given by Morris and Crapo's equations for male FEV1, between Morris and Cherniak for female FEV1 and male FVC and between Morris and Knudson for female FVC. Using 80% of predicted value for female FEV1, up to 35% of tests changed their classification from 'normal' to 'abnormal' upon changing the equation used. A high percentage of tests showed a lower limit of normal defined by the confidence interval under 80% and 70% of predicted value. This study emphasizes the importance of choosing the appropriate reference equation. We do not consider it acceptable to use a fixed percentage of the predicted value as the lower limit of normal because of the great number of patients found to be inappropriately classified.

Adolescent↗
PubMed2004

Serum inhibin B and follicle-stimulating hormone levels as tools in the evaluation of infertile men: significance of adequate reference values from proven fertile men.

Inhibin B and FSH levels in 289 idiopathic infertile men were compared with reference materials consisting of 303 proven fertile men (reference group 1) and 307 healthy men from the general population with unknown fertility status (reference group 2). The diagnostic power of these two serum markers of spermatogenesis was evaluated by the use of receiver operating characteristic plot analysis, and an example of how both markers can be used simultaneously in a bivariate reference chart is presented. Inhibin B levels were significantly lower and FSH levels were significantly higher in the infertile men, compared with either reference group, but with significant overlap, especially with reference group 2. Nevertheless, approximately 50% of the infertile men had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 1, whereas only approximately 25% of the infertile men had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 2. Fourteen and 11% of reference group 2 had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 1, suggesting that a significant number of individuals from the general population with unknown fertility but otherwise healthy may actually be subfertile. In conclusion, 1) proven fertile men constitute the most appropriate reference group in the evaluation of the FSH-inhibin B axis; the sensitivity of these markers to identify infertility increased by approximately 20% when fertile men rather than men from the general population were used as control group; 2) FSH alone had a slightly higher positive predictive value than inhibin B alone, but the positive predictive value were highest when both markers of spermatogenesis were used in an inhibin B/FSH ratio; and 3) a bivariate reference chart is a valuable objective tool in the simultaneous evaluation of FSH and inhibin B as two interrelated markers.

Adult↗
PubMed2005

Reference values from M-mode and Doppler echocardiography for normal Syrian hamsters.

AIMS: Echocardiography has recently been introduced to small animal research, allowing serial measurements of cardiac diseases. In addition, the hamster model has been increasingly used, as it mimics many human heart conditions. However, no reference range of echocardiographic values reflecting normal left ventricular (LV) function exists for hamsters. The purpose of this study was to provide one. METHODS AND RESULTS: The study group consisted of 118 10-week-old, female, Syrian golden hamsters, which underwent high-resolution echocardiography. LV mass was calculated using the corrected cube formula, and LV systolic and diastolic function were assessed by fractional shortening and mitral inflow pulsed-wave Doppler, respectively. The myocardial performance index (MPI) measured the time spent in isovolumic activity and reflected both systolic and diastolic function. The mean+/-SD LV mass, fractional shortening, and MPI were 0.19+/-0.04 g, 44.7+/-6.6%, and 0.39+/-0.1, respectively. E and A waves were differentiated in 52% of all animals. Logistic regression adjusted with a cutoff of 378 bpm revealed that the risk of E/A wave fusion was 35 times greater (95% CI: 12.6; 98.4) in animals with a heart rate >378 bpm. CONCLUSION: This study documents echocardiographic characteristics in normal Syrian hamsters, which can be used as control values for future studies.

Animals↗