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PubMedDate not supplied

Accuracy of self-monitoring of blood glucose: impact on diabetes management decisions during pregnancy.

PURPOSE: This study tested the hypothesis that the accuracy of self-monitoring of blood glucose (SMBG) values of patients with diabetes during pregnancy deviates substantially from reference values. METHODS: The patients' glucose values were measured on 6 different SMBG meters; reference values were from the HemoCue B Glucose Analyzer. Over a 5-year period, 1973 comparisons between SMBG values and reference values were recorded during clinic visits and used for this study. Data were analyzed for percent of values that varied more than +/- 10.5% and +/- 15.5% from the reference value. Out-of-range data at each variance level were analyzed to determine the impact on medical management if decisions were based solely on SMBG values. RESULTS: One third of SMBG readings deviated significantly, which could adversely affect treatment for half of these patients if diabetes management was based on SMBG values. At the 10.5% deviation level, 34% of SMBG meter readings were out of range; 54% of these would have implied erroneous treatment. At the 15.5% deviation level, 18% were out of range; 63% of these would have implied erroneous management. CONCLUSIONS: The accuracy of home meters should be verified at regular intervals, and SMBG values should not be the sole criterion for diabetes management during pregnancy.

Blood Glucose Self-Monitoring↗
PubMed2000

Reference change value for HbA1c in patients with type 2 diabetes mellitus.

We estimated reference change value and steady state disease biological variation of glycohemoglobin (HbA1c) from serial measurements in 47 clinically stable type 2 diabetes patients whose home-measured capillary glucose was stable throughout the study. Whole blood HbA1c assays were performed by turbidimetric inhibition immunoassay. The analytical imprecision (coefficient of variation) was 7.1% and 5.0% for control materials with HbA1c of 5.1% and 10.7%, respectively (n=152). The sampling interval was 6 months. Patients were classified into three groups (good, acceptable and poor control) according to the American Diabetes Association (ADA) clinical practice recommendations of 1999 based on HbA1c reference interval. Steady state disease biological variation for each control group was 7.9%, 5.4% and 3.9%. HbA1c absolute reference change value was 1.42, 1.50 and 1.37%, or as relative reference change value, 29.1%, 24.4% and 17.8%, respectively. The analytical goal, defined as one-half of the biological variation, was lower than 3.9% for well-controlled patients.

Aged↗
PubMed2003

Reference range of hematocrit in the elderly with respect to altitude.

The purpose of this paper is to provide a scientific basis for a unified standard of the reference value of old people's hematocrit in China. The reference values of healthy old people's hematocrit have been collected according to the Wintrobe methods; the relationship between the reference values of old people's hematocrit and altitude has been tested in this paper. It has been found that the reference value of old people's hematocrit increases when the altitude gradually increases, and such relationship is quite significant. The method of mathematical univariate regression analysis is used to deduce two regression equations: Y_1=44.1+0.00351x+/-4.5, Y_2=39.5+0.00298x+/-4.1. If the altitude value of a particular area of China is known, the reference value of old people's hematocrit there can be calculated by means of the regression equations. Furthermore, depending on the altitude, China can be divided into three districts: Qingzang District, Central District and Eastern District.

Aged↗
PubMed2005

Lung volumes in healthy Afro-Caribbean children aged 4-17 years.

Lung volumes in healthy children differ according to their ethnic origin. We wished to determine if any differences in the lung volumes of Afro-Caribbean (AC) children from those predicted by Caucasian reference values disappeared if the results were related to sitting height or to 90% or 77% of lung volumes predicted for height from Caucasian reference values based on standing height. We took, as our working hypothesis, that it is inappropriate to use Caucasian reference values to interpret data from Afro-Caribbean children, and that ethnic-specific reference values are required. This was a prospective, observational study. Subjects included 80 AC children with a median age of 9 (range, 4.3-17.8) years. Standing and sitting height were measured. Lung volumes were measured by body plethysmography (total lung capacity, TLC(pleth); functional residual capacity, FRC(pleth); and vital capacity, VC(pleth)), helium gas dilution (functional residual capacity, (FRC(He)), spirometry (forced expiratory volume in 1 sec, FEV(1)), and forced vital capacity (FVC). The lung volumes of AC children correlated significantly with standing height, but differed significantly from values predicted from Caucasian reference values based on standing height (P < 0.05). Significant differences remained for TLC(pleth), FRC(pleth), FRC(He), RV(pleth), VC(pleth), FEV(1), and FVC when the results were related to sitting height or 90% or 77% of values predicted from Caucasian reference values based on height (P < 0.05). Lung volumes in Afro-Caribbean children should be compared to ethnic-specific reference values.

Adolescent↗
PubMed2001

Vitamin D status and redefining serum parathyroid hormone reference range in the elderly.

Subclinical vitamin D insufficiency is characterized by mild secondary hyperparathyroidism and enhanced risk of osteoporotic fracture. However, although low levels of 25-hydroxyvitamin D (25OHD) are common in otherwise normal elderly people, vitamin D status has not generally been taken into account in the previously published reference values for serum PTH. We measured fasting morning serum (obtained from April through June) PTH, total calcium, albumin, phosphate, creatinine, bone markers, and 25OHD in 280 healthy subjects (140 men and 140 women), aged 60-79 yr. Serum PTH was measured by means of 2 immunoradiometric assays, the Allegro intact PTH assay (Nichols Institute Diagnostics) and the new CAP assay (Scantibodies Laboratory, Inc.). We found a high prevalence (167 of 280; 59.6%) of low 25OHD (< or =30 nmol/L) in these otherwise healthy individuals. The PTH concentrations (95% confidence interval) obtained in the whole group of 280 subjects ranged from 13-64 ng/L for the Allegro assay and from 10-44 ng/L for the CAP assay. In the subjects with a serum 25OHD concentration greater than 30 nmol/L, values for both PTH assays were lower, 10-46 and 9-34 ng/L for the Allegro and the CAP assays, respectively. By using these values as a reference range, approximately 25% of the subjects with a serum 25OHD level of 30 nmol/L or less had a high serum PTH level (whatever the assay), reflecting secondary hyperparathyroidism. This might be missed if the reference PTH values are those obtained in the entire group, as is usually done. These results strongly suggest that vitamin D status should be taken into account when establishing reference values for serum PTH in elderly subjects.

Aged↗
PubMed1994

Assessment of vitamin B6 status of strength and speedpower athletes.

OBJECTIVE: The investigation was designed to obtain information concerning the vitamin B6 status in high-performance athletes. SUBJECTS: Fifty-seven strength and speedpower athletes were available for examination. METHODS: Vitamin B6 status was determined by a 7-day weighed food record, enzyme activity (alpha-EGOT) measurement, whole blood concentrations (Saccharomyces carlsbergenisis and 4-pyridoxinic acid (4-PA) excretion (high-pressure liquid chromatography). RESULTS: The absolute vitamin B6 intake in > 30% of the athletes was below the German recommended dietary allowance (GRDA) and, in relation to the protein intake (GRDA 0.20 mg vitamin B6/g protein), > 60% of the athletes had values below the GRDA. More than 90% of the athletes did not attain the reference value (0.88 nmol/mL) for untrained individuals in vitamin B6 whole blood concentration, and only a few athletes (< 5%) had alpha-EGOT values above the reference value of alpha-EGOT > 1.50). The 4-PA excretion was below the reference value of > 2.73 mumol/g creatinine in 18% of all athletes examined. CONCLUSIONS: Vitamin B6 status can be quantified using the weighed food record, microbiological whole blood determination, and 4-PA excretion; however, limits of the individual methods must be taken into account. Vitamin B6 supply of the athletes still cannot be definitively assessed because there are no generally valid reference values.

Aspartate Aminotransferases↗
PubMedDate not supplied

[Sensitivity, specificity and prognostic value of CEA in colorectal cancer: results of a Tunisian series and literature review].

In order to determine the sensitivity of CEA in the diagnosis of colo-rectal carcinoma, we studied a series of 48 patients with colo-rectal carcinoma (1992-1996). The sensitivity was at 52% with a reference value of 5 ng/ml and 68.7% for a reference value of 2.5 ng/ml. With a reference value of 5 ng/ml, the sensitivity of CEA was at 37% only for patients with colo-rectal carcinoma at Dukes B stage, 66.6% for patients at stage C and 75% for patients at stage D. The dosage of CEA was carried out with a sandwich immunoenzymatic technique in tube. There is no statistic significant correlation between the pre-operative rate of CEA and the localisation of the tumor and its histologic type; in contrast, it was significantly correlated with the ganglionnary metastasis. A significant relationship between the pre-operative rate of CEA and the Dukes stage was found for a reference value of 10 ng/ml but not for a reference value of 5 ng/ml. We calculated the specificity of the CEA for the cancers of colon and rectum which was at 76.98% with a reference value of 5 ng/ml and 86% with a reference value of 10 ng/ml.

Adult↗
PubMed2000

Interpretation of echocardiographic measurements: a call for standardization.

BACKGROUND: Although echocardiography is used extensively in clinical medicine, guidelines for quantitative interpretation of echocardiographic measurements are unavailable. The goals of this investigation were to provide an overview of scientific standards for formulating reference values, with clinical chemistry used as a model, to evaluate published echocardiographic reference limits, to survey clinical echocardiography laboratories regarding their interpretation of echocardiographic measurements, and to provide recommendations for improving the interpretation and reporting of echocardiographic measurements. METHODS AND RESULTS: We reviewed the original reports of the International Federation of Clinical Chemistry on guidelines for formulating reference values. We obtained published reports on echocardiographic reference limits through searches of electronic databases supplemented by a manual search of relevant bibliographies. We also surveyed echocardiographic laboratories in 35 adult acute-care hospitals in Eastern Massachusetts. Studies on echocardiographic reference values were evaluated with the use of guidelines from clinical chemistry. Responses from the 29 participating echocardiographic laboratories were evaluated for their practice of quantitative echocardiographic interpretation. There is considerable heterogeneity in the echocardiographic reference values available in the literature. There is also a lack of agreement in the literature and among echocardiographers regarding the partitioning of reference values (by sex, ethnicity, or age), the anthropometric measure to be used for indexation, and the choice of cut-points for categorizing values within the abnormal range. CONCLUSIONS: We advocate that echocardiographic reference limits be standardized and a consensus generated regarding the partitioning of reference limits and the indexation of echocardiographic measurements. Such measures can aid in quantitative echocardiographic interpretation and render the results more scientific and consistent.

Adolescent↗
PubMedDate not supplied

Discussion on the relationship between normal hematocrit and geographical factors in China.

This paper is written in order to provide a scientific basis for laying out an unified standard of the reference value of hematocrit of Chinese healthy people. It studies the relationship between the reference values of Chinese adults' hematocrit, tested according to the Wintrobe Laws and five geographical factors. It is found that the altitude is the most important factor affecting the reference value of Chinese healthy people's hematocrit. As the altitude gradually increases, the reference value of their hematocrit also increases. By using the method of stepwise regression analysis, two multivariate regression equations are deduced. If the geographical index values in a particular area are known, the reference value of Chinese healthy people's hematocrit in this area can be established by means of the regression equations. Furthermore, according to the dependent relationship of the reference value of Chinese healthy people's hematocrit to geographical factors, China can be divided into six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast district.

Adolescent↗
PubMed1977

Hematologic values in normal pygmy goats.

Pygmy goat blood was analyzed to determine hematologic base-line values. Male, female, and castrated male goats were used in this investigation. Influence of age on these variables was also studied. Most of the hematologic values of pygmy goats were similar to the reference values reported for several other ruminant species and for man. Values significantly different from reference values in man were as follows: Erythrocyte counts were slightly higher than for human beings. The relative lymphocyte count was comparable to that in infants, but significantly greater than values in adult human beings. Also, although not of statistical significance, hemoglobin levels in goats were slightly lower than in both infants and adult human beings, and the leukocyte count was just slightly higher than the usual values for infants and adult human beings. Thus, of 9 hematologic variables, only 1 was significantly different from those in man, and 2 were slightly different. The fact that pygmy goats have hematologic responses similar to those of man, and the similarity of hematologic values to reference values in man, further enhances the pygmy goat for use as an experimental animal.

Animals↗
PubMed1987

Is the turbidimetric immunoassay of haptoglobin phenotype-dependent?

Comparison of the turbidimetric immunoassay of haptoglobin with a reference method (the RID technique with appropriate correction for phenotype) clearly showed the turbidimetric assay to be phenotype-dependent. Correction factors for the three main phenotypes were calculated and reference values determined. The observed overall reference range of haptoglobin, irrespective of the phenotype, was 0.56-3.76 g/L. After correction for phenotype, reference values for the three types were: Hp 1-1: 0.77-2.49; Hp 2-1: 0.86-4.76; and Hp 2-2: 0.48-3.15 g Hp/L. From our reference values for the several phenotypes of haptoglobin it may be argued that phenotyping is desirable only when the uncorrected haptoglobin value, determined by turbidimetry, is within the range 0.38-0.98 g/L. Limited to hemolytic diseases, phenotype determination can be omitted beyond this range.

Haptoglobins↗
PubMed1978

[Distribution pattern, statistical analysis and correlation of selenium levels in swine selenium-indicating organs].

There is a potential risk of excessive selenium levels in organs of swine, resulting in toxicity and residues in pork, or selenium deficit. Therefore, random selenium mean values in "selenium-indicating" organs of pigs selected from suspicious populations were compared with mean and limiting values (reference or normal values) recorded from animals with intact metabolism. Prerequisites required for such comparative assessment included the availability of estimated variance values and knowledge of the presence of abscence of agreement between normal distribution and empirical frequency distribution for the population concerned. Knowledge must be available also on the informative value of measured selenium data in blood plasma and their relevance to the general selenium situation in the organism and muscle at large. These were some of the problems studied by determining selenium levels in the liver, kidneys, blood plasma, and M. longissimus dorsi. Organic selenium concentrations were found to be distributed with right axis deviation but almost normal. The parameters established were typical of the majority of data known from literature. Those date, however, are quite variable, so that the need for independently prepared reference values cannot be abandoned. Correlation analysis showed reciprocal relationships between selenium levels in blooc plasma, liver, and muscles but much less correlation between these, on the one hand, and selenium in kidneys, on the other. The correlations between blood plasma and muscle selenium were close enough to take blood plasma values recorded from the living animal as reference from which to draw conclusions as to the muscular selenium state.

Animals↗
PubMed2005

Normal values for single fiber EMG parameters of frontalis muscle in healthy subjects older than 70 years.

OBJECTIVE: Single fiber EMG (SFEMG) is a potent electrophysiological method to evaluate impaired neuromuscular transmission, and allows sensitive diagnosis of neuromuscular transmission abnormalities such as myasthenia gravis. The jitter and fiber density values are different for various muscles and age groups and the reference values increase with age. In this study, we evaluated the reference values of jitter and fiber density of frontalis muscle in healthy subjects older than 70 years. METHODS: We evaluated the jitter and fiber density of frontalis muscle in 32 healthy subjects. Twenty-two of them were between 70 and 79 years old (mean +/- SD, 73.9 +/- 1.7), and 10 of them were older than 80 years (mean +/- SD, 82.2 +/- 1.2). RESULTS: Normal limit of jitter (95% confidence limit) was calculated as 40.4 micros for healthy subjects between 70 and 79 years old and 43.7 micros for healthy subjects older than 80 years and normal limit of fiber density (95% confidence limit) were calculated as 1.90 for subjects between 70 and 79 years old and 2.14 for subjects older than 80 years. CONCLUSIONS: We designated the reference values of jitter and fiber density for frontalis muscle in healthy subjects older than 70 years. Our reference values may have value to diagnose neuromuscular transmission abnormalities in elderly patients. SIGNIFICANCE: SFEMG is sensitive for neuromuscular transmission abnormalities and it is important to know the reference values of frontalis muscle in healthy subjects older than 70 years.

Aged↗
PubMed2006

Precision and accuracy of two blood glucose meters: FreeStyle Flash versus One Touch Ultra.

PURPOSE: The precision and accuracy of two blood glucose meters were evaluated using finger and forearm blood samples. METHODS: Duplicate blood glucose measurements on the same forearm and finger as venipuncture were performed with the FreeStyle Flash and the One Touch Ultra. Accuracy was assessed by error-grid analysis and the number of values within 10% of the laboratory reference value. Precision was determined by calculating the absolute mean percent differences in glucose values between the first and second fingers and forearm test results. Forearm testing success was defined as an accurate glucose reading obtained with one lance. RESULTS: A total of 100 patients completed the study; 93% had diabetes and 53% were female. Patients' mean +/- S.D. age was 63 +/- 12 years, and glucose measurements ranged from 69 to 354 mg/dL. All finger-stick samples fell within error-grid zones A and B; 72% and 57% of FreeStyle Flash and One Touch Ultra values fell within 10% of the laboratory reference values, respectively (p = 0.027). Forearm samples were successfully obtained in 99 and 74 patients using the FreeStyle Flash and One Touch Ultra (p < 0.001), with 64 and 36 samples, respectively, falling within 10% of the laboratory reference values (p = 0.035). There was no difference in meter precision. CONCLUSION: The FreeStyle Flash and the One Touch Ultra are precise glucose meters; however, the FreeStyle Flash was associated with greater accuracy. Success rates of forearm glucose sampling were significantly greater when the FreeStyle Flash meter was used.

Adult↗
PubMed1999

The relationship between normal erythrocyte sedimentation rate of Chinese young people and geographical factors.

In order to provide a scientific basis for the layout of a unified standard of the reference value of Chinese young people's erythrocyte sedimentation rate (ESR), the relationship between the reference values of the Chinese healthy young's ESR and five geographical factors was tested according to the Wintrobe methods. The altitude was found to be the most important factor affecting the reference value of the Chinese young's ESR. The altitude increase correlates with the decrease of the reference value of the young's ESR. The method of stepwise regression analysis was used to deduce two multivariate regression equations. If the geographical index values of a particular area of China are known, the reference value of the young's ESR of this region can be calculated by means of the regression equations. Furthermore, the depending on geographical factors, China can be divided into six districts: Qingzang, Southwest, Northwest, Southeast, North and Northeast District, according to the reference values of the Chinese young's ESR.

Adult↗
PubMed1985

A comparison of reference method values for sodium, potassium and chloride with method-dependent assigned values.

The concentrations of sodium, potassium, and chloride in various control sera were determined by reference methods. The reference method values were compared with the corresponding method-dependent assigned values. Sodium: Measurements by flame photometry and ion selective electrodes differed on the whole by less than 1% from the reference method value; determinations by photometry differed, however, by -4.7%. Potassium: The mean bias was -1.2% with flame photometry and -0.4% with ion selective electrodes, whereas nephelometric procedures differed by -1.9 or -4.8%. Chloride: Satisfactory agreement was obtained with values given for ion selective electrodes (-0.3%), for some coulometric procedures (-0.7 and 0.4%), and photometric determinations using mercury rhodanide (-0.5 and +0.7%). Values for mercurimetric titration and for photometric determinations using mercury 2,4,6-tri-(2-pyridyl)-s-triazine differed by + 2.5 and + 1.8%. Proposals concerning the allowable deviation from reference method values are discussed.

Chlorides↗
PubMed2003

Study of extremely low frequency electromagnetic fields in infant incubators.

OBJECTIVES: The aim of the work was to present the results of measurements of extremely low frequency electromagnetic fields (ELF EMF), namely the magnetic flux density, inside infant incubators, and to compare these results with the data published by other authors who point out to a possible association between leukemia or other diseases observed in newborns kept in incubators after the birth and the ELF EMF exposure in the incubator. The measured magnetic flux densities were compared with the reference values for this frequency range indicated in the European Union (EU) recommendations. MATERIALS AND METHODS: The repeated measurements in incubators were made with a calibrated magnetometer EFA 300 in the frequency range of 5-30 kHz. Effective values of magnetic flux densities of ELF EMF were determined taking account of the reference values. RESULTS: The results of many repeated measurements showing the values of magnetic flux density in modern incubators with plastic supporting frame, were compared with those obtained in old type incubators with iron skeleton. A power frequency of 50 Hz was detected in the incubator and the ELF EMF values were by over two orders lower than the EU reference values. CONCLUSIONS: The paper emphasizes the need to take a special care of newborns kept in incubators even if only the sub-reference values are detected. The EU reference values are intended for the adult human population. A baby in an incubator has much smaller dimensions, higher electric conductivity and maybe trigger another mechanism of response to ELF EMF than that indicated in this paper.

Electromagnetic Fields↗