Venous Plasma Glucose Concentrations Research Articles

Analytical Performance of the Factory-Calibrated Flash Glucose Monitoring System FreeStyle Libre2TM in Healthy Women.

Continuous glucose monitoring (CGM) is used clinically and for research purposes to capture glycaemic profiles. The accuracy of CGM among healthy populations has not been widely assessed. This study assessed agreement between glucose concentrations obtained from venous plasma and from CGM (FreeStyle Libre2TM, Abbott Diabetes Care, Witney, UK) in healthy women. Glucose concentrations were assessed after fasting and every 15 min after a standardized breakfast over a 4-h lab period. Accuracy of CGM was determined by Bland-Altman plot, 15/15% sensor agreement analysis, Clarke error grid analysis (EGA) and mean absolute relative difference (MARD). In all, 429 valid CGM readings with paired venous plasma glucose (VPG) values were obtained from 29 healthy women. Mean CGM readings were 1.14 mmol/L (95% CI: 0.97 to 1.30 mmol/L, p < 0.001) higher than VPG concentrations. Ratio 95% limits of agreement were from 0.68 to 2.20, and a proportional bias (slope: 0.22) was reported. Additionally, 45% of the CGM readings were within ±0.83 mmol/L (±15 mg/dL) or ±15% of VPG, while 85.3% were within EGA Zones A + B (clinically acceptable). MARD was 27.5% (95% CI: 20.8, 34.2%), with higher MARD values in the hypoglycaemia range and when VPG concentrations were falling. The FreeStyle Libre2TM CGM system tends to overestimate glucose concentrations compared to venous plasma samples in healthy women, especially during hypoglycaemia and during glycaemic swings.

Case–control study of serum vitamin D concentrations in hospitalised patients with COVID-19 and hospitalised controls suffering with respiratory tract infections of differing aetiology

This study explored the prevalence of low serum vitamin D in patients admitted with acute respiratory tract infections (ARTIs) such as COVID-19. This study investigated whether patients with COVID-19 had...

Discordance Between Glucose Levels Measured in Interstitial Fluid vs in Venous Plasma After Oral Glucose Administration: A Post-Hoc Analysis From the Randomised Controlled PRE-D Trial.

AimsThe oral glucose tolerance test (OGTT) is together with haemoglobin A1c (HbA1c) gold standard for diagnosing prediabetes and diabetes. The objective of this study was to assess the concordance between glucose values obtained from venous plasma versus interstitial fluid after oral glucose administration in 120 individuals with prediabetes and overweight/obesity.Methods120 adults with prediabetes defined by HbA1c 39-47 mmol/mol and overweight or obesity who participated in the randomised controlled PRE-D trial were included in the study. Venous plasma glucose concentrations were measured at 0, 30, 60 and 120 minutes during a 75 g oral glucose tolerance test (OGTT) performed on three different occasions within a 26 weeks period. During the OGTT, the participants wore a CGM device (IPro2, Medtronic), which assessed glucose concentrations every five minutes.ResultsA total of 306 OGTTs with simultaneous CGM measurements were obtained. Except in fasting, the CGM glucose values were below the OGTT values throughout the OGTT period with mean (SD) differences of 0.2 (0.7) mmol/L at time 0 min, -1.1 (1.3) at 30 min, -1.4 (1.8) at 60 min, and -0.5 (1.1) at 120 min). For measurements at 0 and 120 min, there was a proportional bias with an increasing mean difference between CGM and OGTT values with increasing mean of the two measurements.ConclusionsDue to poor agreement between the OGTT and CGM with wide 95% limits of agreement and proportional bias at 0 and 120 min, the potential for assessing glucose tolerance in prediabetes using CGM is questionable.

Continuous renal replacement therapy: a potential source of calories in the critically ill ,

Background: Overfeeding can lead to multiple metabolic and clinical complications and has been associated with increased mortality in the critically ill. Continuous venovenous hemofiltration (CVVH) represents a potential source of calories that is poorly recognized and may contribute to overfeeding complications.Objective: We aimed to quantify the systemic caloric contribution of acid-citrate-dextrose regional anticoagulation and dextrose-containing replacement fluids in the CVVH circuit.Design: This was a prospective study in 10 critically ill adult patients who received CVVH from April 2014 to June 2014. Serial pre- and postfilter blood samples (n = 4 each) were drawn and analyzed for glucose and citrate concentrations on each of 2 consecutive days.Results: Participants included 5 men and 5 women with a mean ± SEM age of 61 ± 4 y (range: 42-84 y) and body mass index (in kg/m2) of 28 ± 2 (range: 18.3-36.2). There was generally good agreement between data on the 2 study days (CV: 7-11%). Mean ± SEM pre- and postfilter venous plasma glucose concentrations in the aggregate group were 152 ± 10 and 178 ± 9 mg/dL, respectively. Net glucose uptake from the CVVH circuit was 54 ± 5 mg/min and provided 295 ± 28 kcal/d. Prefilter plasma glucose concentrations were higher in patients with diabetes (n = 5) than in those without diabetes (168 ± 12 compared with 140 ± 14 mg/dL; P < 0.05); however, net glucose uptake was similar (46 ± 8 compared with 61 ± 6 mg/min; P = 0.15). Mean ± SEM pre- and postfilter venous plasma citrate concentrations were 1 ± 0.1 and 3.1 ± 0.2 mmol/L, respectively. Net citrate uptake from the CVVH circuit was 60 ± 2 mg/min and provided 218 ± 8 kcal/d.Conclusions: During CVVH there was a substantial net uptake of both glucose and citrate that delivered exogenous energy and provided ∼512 kcal/d. Failure to account for this source of calories in critically ill patients receiving nutrition on CVVH may result in overfeeding.

Effects of maternal age, parity and pre-pregnancy body mass index on the glucose challenge test and gestational diabetes mellitus.

ObjectivesTo study the effects of age, parity and body mass index (BMI) on the incidence of a positive 50 g glucose challenge test (OGCT) and gestational diabetes mellitus (GDM) in healthy pregnant Omani women.MethodsA 50 g OGCT was performed on 307 healthy pregnant Omani women at 24–28 weeks of gestation. When the venous plasma glucose concentration (VPG) reached >7.8 mmol/l after 1 h, the OGCT was considered to be positive. Women with positive OGCTs had a confirmatory diagnosis of GDM, which was established by performing a 2-h 75 g oral glucose tolerance test (OGTT). When either fasting or post-2-h 75 g OGTT values were >5.5 mmol/l or >8 mmol/l, respectively, women were considered diabetic.ResultsThis study screened 307 women and identified 83 (27.03%) OGCT-positive and 23 (7.5%) GDM-positive cases. The incidences of a positive OGCT and GDM increased significantly with increasing maternal age from 20.0% to 2.2%, respectively, in women aged ≤25 years to 37.8% and 14.7%, respectively, in women aged >35 years (p = 0.02 and p = 0.009, respectively). The incidences of a positive OGCT and GDM increased markedly with increasing pre-pregnancy BMI, from 19.8% to 3.8%, respectively, in women with BMIs ≤25 kg/m2 to 37.8% and 9.9%, respectively, in women with BMIs >25 kg/m2 (p = 0.02 and p = 0.04, respectively).ConclusionMaternal age and pre-pregnancy BMI have profound effects on the incidences of a positive OGCT and GDM.

Unreliable Fingerstick Glucose Measurement in Systemic Sclerosis

ABSTRACT Objective: A female with systemic sclerosis was found to have apparent hypoglycemia on fingerstick blood glucose measurements while being asymptomatic. Methods: Clinical assessment, laboratory studies, and glucose-meter testing performed in clinic presented in addition to a brief literature review. Results: Per glucometer, glucose measurements increased with more proximal blood sampling on the right upper extremity, revealing values of 33, 68, and 77 mg/dL. Simultaneous venous laboratory blood glucose was 89 mg/dL. In addition, an evaluation for possible insulinoma yielded negative laboratory values. Conclusion: Certain conditions of impaired microcirculation can result in a spurious discrepancy between capillary glucose values and venous plasma glucose concentrations, a state known as pseudohypoglycemia. Awareness of damaged microvasculature in connective tissue disorders may prevent unnecessary workup of pseudohypoglycemia.

Postprandial capillary-venous glucose gradient in Type 1 diabetes: magnitude and clinical associations in a real world setting.

AimsTo determine the magnitude of the peripheral glucose gradient in patients with Type 1 diabetes in a real world setting and to explore its relationship with insulin dose and macronutrient intake.MethodsAll patients used mealtime analogue insulin. The glucose gradient was assessed using antecubital fossa venous and finger‐stick capillary samples, collected concurrently at room temperature. Baseline sampling occurred before the administration of an insulin dose and breakfast of the patient's choosing. Breakfast was consumed an average of 15 min after baseline. The macronutrient content of breakfast was documented. Sampling was repeated 1 and 2 h after baseline.ResultsThe mean (95% CI) plasma capillary–venous glucose gradient values for 43 patients were: pre‐breakfast, 0.21 (0.08–0.34) mmol/l; 1 h after baseline, 0.87 (0.66–1.07) mmol/l; and 2 h after baseline, 0.52 (0.33–0.71) mmol/l. Glucose gradient and dietary carbohydrate intake (g/kg body weight) were positively correlated at both 1 h (P < 0.01) and 2 h after baseline (P < 0.01). No relationship was observed between this gradient and mealtime insulin dose, or the glucose concentration at either time point.ConclusionsIn patients with Type 1 diabetes, a clinically significant glucose gradient is present after the ingestion of a carbohydrate‐rich meal. As postprandial capillary and venous plasma glucose concentrations are not equivalent, defining the site of sample collection is important.

50 Grams Oral Glucose Challenge Test: Is It an Effective Screening Test for Gestational Diabetes Mellitus?

To find out whether 50g oral glucose challenge test (OGCT) is an effective screening test for all pregnant women between 24 and 28weeks gestation. A 50g OGCT test was administered to 307 unselected women at 24-28weeks of gestation. When venous plasma glucose (VPG) concentration after 1h was>7.8mmol/l, OGCT was positive. Women with a positive OGCT underwent 2 h 75grams oral glucose tolerance test (OGTT) as a confirmatory diagnosis of GDM. When fasting and 2h post 75 g OGTT values were>5.5mmol/I and>8mmol/l, respectively, women were considered diabetic. We screened 307 women for GDM by OGCT. Total number of women with positive OGCT was 83 (27.03%). In the low-risk group, total number of women with GDM was 9/168 (5.35%) while the total number of women with GDM in the high-risk group was 14/139 (10.07%). There was no significant difference with respect to the total number of women with GDM in the groups. A 50g OGCT seems to be an effective screening test for both groups. More cases of GDM can be discovered when universal rather than risk-related screening is applied.

Upregulation of skeletal muscle inflammatory genes links inflammation with insulin resistance in women with the metabolic syndrome

The metabolic syndrome, a combination of interrelated metabolic risk factors, is associated with insulin resistance and promotes the development of cardiovascular diseases and type 2 diabetes mellitus. There is a close link between inflammation and metabolic disease, but the responsible mechanisms remain elusive. The aim of this study was to identify differentially expressed genes in insulin-resistant skeletal muscle tissue of women with the metabolic syndrome compared with healthy control women. Women with the metabolic syndrome (n = 19) and healthy control women (n = 20) were extensively phenotyped, insulin sensitivity was measured using a hyperinsulinaemic euglycaemic clamp, and a skeletal muscle biopsy was obtained. Gene expression levels were compared between the two groups by microarrays. The upregulated genes in skeletal muscle of the women with the metabolic syndrome were primarily enriched for inflammatory response-associated genes. The three most significantly upregulated of this group, interleukin 6 receptor (IL6R), histone deacetylase 9 (HDAC9) and CD97 molecule (CD97), were significantly correlated with insulin resistance. Taken together, these findings suggest an important role for a number of inflammatory-related genes in the development of skeletal muscle insulin resistance.

Effective inhibition of glycolysis in venous whole blood and plasma samples1)

Abstract Background: To stabilize glucose immediately and to prevent preanalytical loss of glucose from blood samples after collection, additional acidification is needed. Methods: In this study, we aimed to assess the value of citrate-buffered GlucoEXACT tubes (Sarstedt) compared to VenoSafe™ Glycaemia (Terumo) tubes. Conventional sodium fluoride (NaF) tubes were used as internal controls. First, stability of venous plasma glucose concentrations were compared in 10 healthy volunteers at nine definite time points (after 0, 0.5, 1, 1.5, 2, 3, 4, 8, and 12 h). Blood samples from VenoSafe™ Glycaemia and NaF tubes were immediately centrifuged and separated. Moreover, glucose concentrations in an additional five healthy volunteers were compared by collecting blood samples simultaneously in GlucoEXACT and VenoSafe™ Glycaemia tubes and storing for 0, 1, 2, 4, 12, 24, and 48 h until centrifugation. Dilution- and hematocrit-dependent bias of plasma glucose in GlucoEXACT tubes was assessed by serial dilution. Results: Mean Terumo plasma glucose concentrations decreased within the first 4 h from 94.9 mg/dL to 92.5 mg/dL (–2.5%) and remained stable after 12 h. Mean conventional NaF plasma glucose concentrations decreased within the first 4 h from 90 mg/dL to 87 mg/dL (–3.3%, not significant) and decreased significantly after 12 h (82.6 mg/dL, –8.2%). There was no significant decrease or difference of plasma glucose levels in stored blood samples collected in GlucoEXACT and VenoSafe™ Glycaemia tubes [linear regression analysis: R2=0.9688; GlucoEXACT (y)=5.3871+0.9431× VenoSafe™ Glycaemia (x); Wilcoxon test, p=0.7125]. Citrate buffer in GlucoEXACT tubes does not impair glucose concentration. Conclusions: Determination of plasma glucose concentration in GlucoEXACT tubes is a suitable diagnostic alternative compared with Terumo VenoSafe™ Glycaemia tubes.

A forage-only diet alters the metabolic response of horses in training

Most athletic horses are fed a high-starch diet despite the risk of health problems. Replacing starch concentrate with high-energy forage would alleviate these health problems, but could result in a shift in major substrates for muscle energy supply from glucose to short-chain fatty acids (SCFA) due to more hindgut fermentation of fibre. Dietary fat inclusion has previously been shown to promote aerobic energy supply during exercise, but the contribution of SCFA to exercise metabolism has received little attention. This study compared metabolic response with exercise and lactate threshold (VLa4) in horses fed a forage-only diet (F) and a more traditional high-starch, low-energy forage diet (forage–concentrate diet - FC). The hypothesis was that diet F would increase plasma acetate concentration and increase VLa4 compared with diet FC. Six Standardbred geldings in race training were used in a 29-day change-over experiment. Plasma acetate, non-esterified fatty acids (NEFA), lactate, glucose and insulin concentrations and venous pH were measured in samples collected before, during and after a treadmill exercise test (ET, day 25) and muscle glycogen concentrations before and after ET. Plasma acetate concentration was higher before and after exercise in horses on diet F compared with diet FC, and there was a tendency (P = 0.09) for increased VLa4 on diet F. Venous pH and plasma glucose concentrations during exercise were higher in horses on diet F than diet FC, as was plasma NEFA on the day after ET. Plasma insulin and muscle glycogen concentrations were lower for diet F, but glycogen utilisation was similar for the two diets. The results show that a high-energy, forage-only diet alters the metabolic response to exercise and, with the exception of lowered glycogen stores, appears to have positive rather than negative effects on performance traits.

Evaluation of the relationship between capillary and venous plasma glucose concentrations obtained by the HemoCue Glucose 201+ system during an oral glucose tolerance test

In 55 women with previous gestational diabetes mellitus, simultaneous capillary and venous plasma glucose concentrations were measured at 0, 30 and 120 min during a 75 g oral glucose tolerance test (OGTT). The aims of the study were to examine the relationship between capillary and venous glucose measurements, and to establish equations for the conversion of capillary and venous glucose concentrations using the HemoCue Glucose 201+ system. Additionally, the correlation between the capillary and venous glucose concentrations with the diagnostic cut-off limits proposed by the World Health Organization (WHO) in 1999 was evaluated. Capillary glucose concentrations were consistently higher than venous glucose concentrations at all time points of the OGTT (p < 0.001), and the correlations between the measurements were statistically highly significant (p < 0.001). The differences between the samples were greatest in the non-fasting state as revealed by the 95% prediction intervals (mmol/L) in Bland-Altman plots; ± 0.54 at 0 min, ± 2.01 at 30 min, and ± 1.35 at 120 min. Equivalence values for capillary plasma glucose concentrations derived from this study tended to be higher than those proposed by the WHO as diagnostic cut-off limits. Stratifying subjects by glucose tolerance status according to the WHO criteria revealed disagreements related to glucose values close to the diagnostic cut-off points. The study findings highlight the uncertainty associated with derived equivalence values. However, capillary plasma glucose measurements could be suitable for diagnostic purposes in epidemiological studies and when translating results on a group basis.

Postprandial glucose, insulin and glucagon-like peptide 1 responses to sucrose ingested with berries in healthy subjects

Berries are often consumed with sucrose. They are also rich sources of polyphenols which may modulate glycaemia after carbohydrate ingestion. The present study investigated the postprandial glucose, insulin and glucagon-like peptide 1 (GLP-1) responses to sucrose ingested with berries, in comparison with a similar sucrose load without berries. A total of twelve healthy subjects were recruited to a randomised, single-blind, placebo-controlled crossover study. They participated in two meal tests on separate days. The berry meal was a purée (150 g) made of bilberries, blackcurrants, cranberries and strawberries with 35 g sucrose. The control meal included the same amount of sucrose and available carbohydrates in water. Fingertip capillary and venous blood samples were taken at baseline and at 15, 30, 45, 60, 90 and 120 min after starting to eat the meal. Glucose, insulin and GLP-1 concentrations were determined from the venous samples, and glucose also from the capillary samples. Compared to the control meal, ingestion of the berry meal resulted in lower capillary and venous plasma glucose and serum insulin concentrations at 15 min (P = 0·021, P < 0·007 and P = 0·028, respectively), in higher concentrations at 90 min (P = 0·028, P = 0·021 and P = 0·042, respectively), and in a modest effect on the GLP-1 response (P = 0·05). It also reduced the maximum increases of capillary and venous glucose and insulin concentrations (P = 0·009, P = 0·011 and P = 0·005, respectively), and improved the glycaemic profile (P < 0·001 and P = 0·003 for capillary and venous samples, respectively). These results suggest that the glycaemic control after ingestion of sucrose can be improved by simultaneous consumption of berries.

The Diagnosis of Diabetes Is Changing: How Implementation of Hemoglobin A1c Will Impact Clinical Laboratories

The earliest known description of diabetes mellitus is in the Papyrus of Ebers by Hesy-Ra in 1552 BC. Since then, we have learned that diabetes consists of a group of metabolic disorders, all of which produce hyperglycemia. The relatively specific complications of diabetes (affecting the eyes, kidneys, and nervous system) and the high prevalence (estimated at approximately 40 × 106 in the US and approximately 250 × 106 worldwide) combine to make it a substantial public health problem. Our comprehension of the pathophysiology of the disease is limited, however, and no biological marker is known to be unique to diabetes. Diagnosis has been based exclusively on the demonstration of increased glucose concentrations, initially in urine and subsequently in the blood. Therefore, the recent publication of the International Expert Committee report on the diagnosis of diabetes (1), which recommends the use of hemoglobin A1c (Hb A1c)1 rather than glucose for the diagnosis of diabetes, represents a dramatic change that deserves reflection. Hyperglycemia has been the sole diagnostic criterion for diabetes since the development of blood glucose assays 100 years ago. Measurement of the response to a metabolic challenge in the form of the oral glucose tolerance test (OGTT) was initially used. The cutoff was 2 SDs above the mean glucose concentration in healthy individuals. This strategy was limited by a lack of standardization in both the performance and the interpretation of the test and its poor reproducibility. In 1979, the National Diabetes Data Group proposed criteria that were derived from the distribution of glucose concentrations in populations with a high prevalence of diabetes (2). The diagnostic criteria were ( a ) classic symptoms of diabetes with an unequivocal increase in plasma glucose, ( b ) a venous fasting plasma glucose (FPG) concentration ≥7.8 mmol/L (140 mg/dL), or ( c ) a …

The glycaemic response to rolled oat is not influenced by the fat content

Oat is promoted as a low-glycaemic index food. Our aim was to measure the effect of the fat content of oat in glycaemia and insulinaemia and compare it with the effect of wheat. The study design was a double-blind, randomised cross-over study with four treatment segments. Eight healthy males attended four study sessions in which porridge made from four different raw materials was consumed: rolled oat (O), defatted rolled oat (DO), rolled whole wheat (W) or rolled whole wheat with added oat fat (WF). Available carbohydrate content was analysed enzymatically, and was adjusted to 50 g in each test meal. Fat content per meal was either 6.1 g (O, WF) or approximately 1.9 g (W, DO). Venous plasma glucose, insulin and triacylglycerol concentrations were measured at 0, 30, 60, 90, 120 and 180 min. All products caused a rapid increase in glucose with a peak at 30 min, where W and WF were significantly higher than O (0 = 0.006). Also insulin peaked at 30 min (no differences). A 4.2 g difference in fat content between O and DO or W and WF did not result in any significant differences in their glycaemia or insulinaemia. W and O did not differ in their overall glycaemic or insulinaemic responses. The removal of two-thirds of oat fat did not affect the postprandial plasma triacylglycerol concentration. The present study shows that neither the glycaemic nor the insulinaemic response to rolled oat is affected by the fat content, and that rolled wheat differed from rolled oat in terms of peak glucose concentration only.

50 gram oral glucose challenge test combined with risk factor-based screening for gestational diabetes

Objective: Our aim was to study whether universal screening of all pregnant women by Oral Glucose Challenge Test (OGCT) would identify a higher number of women with Gestational Diabetes (GDM) than risk factor based screening. Study design: A 50 g OGCT test was performed prospectively in 532 unselected women at 26–28 weeks of gestation. The 1-h venous plasma glucose concentration of >7.3 mmol/l was considered as a positive screening result. Patients with a positive OGCT underwent a 75 g 2-h OGTT, which was used as the actual diagnostic test for GDM. When two or all three of the glucose concentrations in OGTT (measured at fasting state and 1 and 2 h after the 75 g glucose load) were above the 97.5th percentile the patient was considered as having GDM. In addition, women with risk factors for GDM also underwent a 75 g OGTT regardless of the result of the OGCT. Results: A positive 50 g OGCT was obtained in 123 (23%) of the women. In 15 (12%) of these, a diagnosis of GDM was established by the subsequent OGTT. Out of the 409 remaining women with a normal OGCT, 148 (36%) had risk factors for GDM. An OGTT performed in these patients identified 4 additional women with a GDM. Seventy-nine percent of GDM was thus found with 50 g OGCT without regarding risk factors. Forty-seven percent of the women with GDM would have been missed in screening by risk factors only. Conclusions: In our population 50 g OGCT appears to identify a higher number of GDM than risk factor based screening. Combined with risk factor screening a few more cases of GDM would be found.

Point‐of‐care testing of HbA1c and blood glucose in a remote Aboriginal Australian community

To assess the accuracy of point-of-care (POC) measurements of capillary blood glucose and glycosylated haemoglobin (HbA(1c)) levels in a remote Aboriginal community with high diabetes prevalence. Cross-sectional study comparing POC capillary glucose and HbA(1c) results with those from corresponding venous samples measured in a reference laboratory. 152 residents aged 11-76 years (representing 76% of population aged over 11 years) had POC glucose measurement in November 2003; 88 with POC glucose level > or = 5.0 mmol/L, or self-reported diabetes, had POC HbA(1c) and laboratory glucose and HbA(1c) measurements. POC fasting capillary levels of glucose (HemoCue Glucose 201 analyser, Medipac Scientific, Sydney) and HbA(1c) (DCA 2000+ analyser, Bayer Australia, Melbourne); correlation and mean difference between capillary POC and venous blood laboratory measurements of glucose and HbA(1c). Mean and median POC capillary glucose levels were 7.99 mmol/L and 6.25 mmol/L, respectively, while mean and median laboratory venous plasma glucose concentrations were 7.63 mmol/L and 5.35 mmol/L. Values for POC capillary HbA(1c) and laboratory HbA(1c) were identical: mean, 7.06%; and median, 6.0%. The correlation coefficient r for POC and laboratory results was 0.98 for glucose and 0.99 for HbA(1c). The mean difference in results was 0.36 mmol/L for glucose (95% CI, 0.13-0.62; limits of agreement [LOA], - 2.07 to 2.79 mmol/L; P = 0.007) and < 0.01% for HbA(1c) (95% CI, - 0.07% to 0.07%; LOA, - 0.66% to 0.66%; P = 0.95), respectively. POC capillary HbA(1c) testing, in particular, offers an accurate, practical, community-friendly way of monitoring diabetes in rural and remote clinical settings. POC capillary glucose results should be confirmed by a laboratory test of venous plasma if the results are likely to significantly influence clinical decisions.

The Prevalence of Diabetes and Impaired Glucose Tolerance in Sivas, Central Anatolia, Turkey

The aim of this study was to determine type 2 diabetes, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) prevalence in Sivas, Turkey. This cross-sectional study was conducted in the city center of Sivas. The study population of 771 subjects was selected by the cluster sampling method from 115,998 individuals aged > or =30 years. Participants with fasting venous plasma glucose concentrations <100 mg/dl were classified as "normal." Diabetes was diagnosed in participants if they had fasting blood glucose levels > or =126 mg/dl. An oral glucose tolerance test (OGTT) was performed in subjects with fasting blood glucose levels > or =100 mg/dl and <126 mg/dl. According to the fasting blood glucose levels of the 771 subjects, 44 (5.7%) had diabetes. OGTTs were performed in 80 (10.4%) subjects. According to OGTT results, there were 5 subjects with diabetes, 20 subjects with IGT (2.6%), and 55 subjects with IFG (7.1%). The combined prevalence of IFG and IGT was 9.7%. After OGTT, the total number of diabetic subjects was determined to be 49 (6.4%). Twenty-four (3.1%) of the subjects had a previous diagnosis of diabetes. Multivariate analyses showed that age, sex, hypertension, cigarette smoking, obesity, and family history of diabetes were risk factors for type 2 diabetes (P < 0.05). Diabetes incidence increases with changes in dietary habits and lifestyle. Education is particularly important for public health, as the community may then have required knowledge about the disease and its risk factors.

Inhibition of endogenous nitric oxide production influences ovine hindlimb metabolism independently of insulin concentrations.

The hindlimb arteriovenous difference (AVD) model was used to determine whether 30 mg/ kg of the nitric oxide synthase (NOS) inhibitor L-NGnitroarginine methyl ester (hydrochloride; L-NAME) inhibited ovine NO synthesis and influenced muscle metabolism. Eight Border Leicester x Merino cross lambs (50 to 55 kg BW) were infused with saline (control) or saline containing L-NAME via an indwelling jugular vein catheter in a balanced randomized crossover design with 3 d between treatments. The abdominal aorta and deep femoral vein were catheterized for assessment of AVD of hind limb metabolism. Arterial hematocrit and insulin concentration and both arterial and venous concentrations of nitrate/nitrite (NOx), glucose, lactate, NEFA, and urea were determined. Infusion of L-NAME decreased arterial NOx concentrations (P = 0.049), indicating inhibition of systemic NO synthesis. Treatment had no effect on arterial (3.5 vs. 3.6 +/- 0.19 mmol/L for control and L-NAME lambs, respectively; P = 0.39) or venous (3.3 vs. 3.4 +/- 0.16 mmol/L, P = 0.55) plasma glucose concentrations or on glucose AVD (0.19 vs. 0.27 +/- 0.065 mmol/L, P = 0.20). There was an interaction (P = 0.038) between time and treatment, such that L-NAME initially increased the AVD of glucose (up to 180 m) divergent from control lambs. The response was then decreased before a possible inflection beyond 240 min. Infusion of L-NAME increased hindlimb venous NEFA (222 vs. 272 +/- 13.2 micromol/L, P = 0.007) and NEFA AVD (79.4 vs. -13.3 +/- 31.5 micromol/L, P = 0.018). These metabolic changes were independent of plasma insulin concentrations, which were not affected by L-NAME infusion (25.3 vs. 27.8 +/- 3.62 mU/L, P = 0.85). The increase in hindlimb lipolysis after L-NAME infusion does not seem to be due to increased lipolysis of plasma triacylglycerol because circulating arterial (155 vs. 142 +/- 20.8 micromol/L, P = 0.58), venous (154 vs. 140 +/- 20.5 micromol/L, P = 0.50), and AVD (1.0 vs. 2.9 +/- 3.17 micromol/L, P = 0.38) triacylglycerol concentrations were unaffected by L-NAME infusion. In conclusion, these data indicate that infusion of 30 mg of L-NAME/kg inhibits NO synthesis, which in turn influences fat and carbohydrate metabolism in the ovine hindlimb independently of plasma insulin concentrations.

Validation of capillary glucose measurements to detect glucose intolerance or type 2 diabetes mellitus in the general population

Background: The use of an oral glucose tolerance test (OGTT) has been recommended to diagnose type 2 diabetes, but an OGTT with venous blood sampling may not be feasible in the screening phase preceding large epidemiological studies. We have conducted a population-based screening in 2715 men and women and evaluated the diagnostic validity of capillary plasma glucose concentration measurements versus venous plasma glucose concentration measurements in a subset of 350 subjects. Methods: During a single OGTT, glucose concentrations were measured in venous plasma as well as in capillary plasma. Results: Based on the 1999 WHO criteria for venous glucose concentrations, the study population ( n=350) yielded 97 subjects with type 2 diabetes mellitus, 77 subjects with impaired glucose tolerance and 176 subjects with normal glucose tolerance. Sensitivity and specificity to diagnose type 2 diabetes mellitus by capillary plasma were 84% and 98%, respectively. Consistent classification by either venous or capillary plasma glucose measurements was 78% ( κ=0.65, p<0.001). Conclusion: Capillary glucose measurements are suitable for use in epidemiological studies to diagnose and detect type 2 diabetes and normal glucose tolerance. Use of capillary measurements can result in cost-effective inclusion schemes in epidemiological studies.