Dynamics of brain natriuretic peptide in critically ill patients with severe sepsis and septic shock.

PURPOSE: Changes of B-type natriuretic peptide (BNP) in sepsis and its utility in predicting intensive care unit outcomes remains a conflicting issue. To investigate the changes in plasma levels of BNP in patients with severe sepsis/septic shock and to study the association of BNP levels with the severity of the disease and prognosis of those patients. METHODS: Thirty patients with severe sepsis or septic shock were enrolled in our study. BNP measurements and echocardiography were carried out on admission and on 4(th) and 7(th) days. Blood concentrations of BNP were measured by commercially available assays (Abbott methods). In-hospital mortality and length of stay were recorded multivariate analyses adjusted for acute physiology and chronic health evaluation score II (APACHE II score) was used for mortality prediction. RESULTS: Twenty patients admitted with the diagnosis of severe sepsis and 10 patients with septic shock. The in-hospital mortality was 23.3% (7 patients). Admission BNP was significantly higher in the non-survivors 1123±236.08 versus 592.7±347.1 (P<0.001). By doing multivariate logestic regression, the predicatable variables for mortality was APACHE II score, BNP, and then EF. CONCLUSION: BNP concentrations were increased in patients with severe sepsis or septic shock and poor outcome was associated with high BNP levels; thus, it may serve as a useful laboratory marker to predict survival in these patients.

Gestational diabetes in a tertiary care hospital: implications of applying the IADPSG criteria.

BACKGROUND: The American Diabetes Association has endorsed the International Association of Diabetes and Pregnancy Groups (IADPSG) recommendation that every pregnant woman should undergo the 75 g oral glucose tolerance test (OGTT) to screen for gestational diabetes mellitus (GDM). PURPOSE: To find the cost and workload implications of switching from the current two-step screening of GDM to the one-step IADPSG approach. METHODS: The cost (US $) and laboratory workload units (WLU) were calculated for three possible strategies: (1) 50 g glucose screen, if positive, followed by the 100 g OGTT; (2) universal 75 g OGTT; and (3) screening with the initial fasting plasma glucose of the OGTT. RESULTS: For the 1,101 pregnant women screened in 1 year, the cost of the three strategies was $ 31,985, $ 55,250 and $ 35,875, respectively; the laboratory burden was 28,975 WLU, 18,662 WLU and 12,215 WLU, respectively. CONCLUSIONS: Switching to the one-step, strategy 2 (IADPSG) would increase the cost by 42 % but decrease the laboratory workload by 36 % compared to the two-step, strategy 1. However, an initial screen by the fasting plasma glucose of the OGTT is the ideal strategy, both in terms of cost and laboratory workload.

Performance of the Roche Accu-Chek active glucose meter to screen for gestational diabetes mellitus using fasting capillary blood.

BACKGROUND: Point-of-care (POC) blood glucose measurement using glucose meters is used by diabetes patients to mange their disease. POC glucose testing also is also used in tight glycemic control protocols and as a screening tool for diabetes. We report the performance and effectiveness of the Accu-Chek® Active (Roche Diagnostics GmbH, Mannheim, Germany) glucose meter to screen for gestational diabetes mellitus (GDM) using blood fasting capillary glucose (FCG). METHODS: To screen for GDM, 1,465 pregnant women underwent an oral glucose glucose tolerance test. Correlation between the FCG and fasting plasma glucose (FPG) levels was determined by Passing and Bablok regression analysis. Total error (TE) of the glucometer was ascertained using the Bland-Altman method with the DXC-800 analyzer (Beckman-Coulter Instruments, Brea, CA) as the reference method. The area under the receiver operator characteristic curve was used to analyze the performance of the FCG to predict GDM. RESULTS: FPG and FCG identified 361 (24.6%) and 338 (23%) women as having GDM, respectively. The Bland-Altman TE at 95% limits of agreement was -11.1% to 10.8%. The area under the receiver operator characteristic curve was 0.953 (95% confidence interval 0.943 to 0.964). CONCLUSIONS: The Roche Accu-Chek Active glucometer meets analytical and clinical quality requirements. A TE of±15% is acceptable for glucose meters used in ambulatory care, including home self-monitoring of blood glucose, and different TE targets should be set for acute critical care settings.

Gestational diabetes: an evaluation of serum fructosamine as a screening test in a high-risk population.

AIM: To evaluate the value of serum fructosamine as a screening test for gestational diabetes mellitus (GDM). METHODS: 849 pregnant women underwent the one-step 75 g oral glucose tolerance test (OGTT) for universal screening of GDM. The fasting serum fructosamine (cFruc) was assessed using the area under the receiver operating characteristic curve (AUC). The GDM diagnostic criteria used were those of the American Diabetes Association; however, the cFruc performance was also evaluated using criteria of the World Health Organization, Australian (ADIPS), European (EASD) and International Association of Diabetes and Pregnancy Study Groups (IADPSG). RESULTS: 113 (13.3%) women had GDM. The AUC of the cFruc was 0.60 (95% CI 0.54-0.66). A cFruc threshold of 237 µmol/l achieved an acceptable sensitivity of 85.8% (95% CI 78.0-91.0%), but the associated specificity remained poor at 23.4% (95% CI 20.0-27.0%) with a positive predictive value of just 14.7%. Overall, over 4 out of 5 pregnant women, being over this cutoff, would need the confirmatory OGTT. No cFruc threshold reached acceptable likelihood ratios to rule-in or rule-out GDM. The AUC for cFruc remained unacceptable independent of the diagnostic criteria. CONCLUSIONS: Despite all the advances in technology, serum fructosamine is a poor test to screen for GDM.

Gestational diabetes mellitus: simplifying the international association of diabetes and pregnancy diagnostic algorithm using fasting plasma glucose.

OBJECTIVE: To determine the impact of the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria on 1) gestational diabetes mellitus (GDM) diagnosis compared with the American Diabetes Association (ADA) criteria and 2) the fasting plasma glucose (FPG) to predict GDM. RESEARCH DESIGN AND METHODS: In 10,283 pregnant women undergoing a 75-g oral glucose tolerance test (OGTT) for universal screening of GDM, two FPG thresholds (of the OGTT) were used to rule in and to rule out GDM. RESULTS: The IADPSG and ADA criteria identified GDM in 3,875 (37.7%) women and 1,328 (12.9%) women, respectively (P < 0.0005). FPG thresholds of >or=5.1 mmol/l ruled in GDM in 2,975 (28.9%) women with 100% specificity, while <4.4 mmol/l ruled out GDM in 2,228 (21.7%) women with 95.4% sensitivity. FPG independently could have avoided the OGTT in 5,203 (50.6%) women. CONCLUSIONS: The IADPSG criteria increased GDM prevalence nearly threefold. By circumventing a significant number of OGTTs, an initial FPG can greatly simplify the IADPSG diagnostic algorithm.

Gestational diabetes: using a portable glucometer to simplify the approach to screening.

BACKGROUND: In populations at a high-risk for gestational diabetes (GDM), the recommendation of screening every pregnant woman with the oral glucose tolerance test (OGTT) is very demanding. AIM: To assess the usefulness of the portable, plasma optimized glucometer in simplifying the approach to screening of GDM. METHODS: 1,662 pregnant women underwent the one-step 75 g OGTT for routine screening of GDM, as defined by the criteria of the American Diabetes Association. The glucometer was used to measure the initial fasting venous whole blood glucose (FBG) to assess its value as a screening test in predicting the need to proceed with the OGTT. RESULTS: 186 (11.2%) women had GDM. The area under the receiver operating characteristic curve (AUC) of the FBG was 0.876 (95% CI 0.847-0.906). A FBG threshold (at an acceptable sensitivity of 85%) independently could 'rule-out' GDM in 1,138 (68.5%) women; i.e. over two-thirds of the women would not need to continue with the cumbersome OGTT. CONCLUSIONS: Using the glucometer to initially measure the venous FBG as a screen can help to significantly reduce the number of OGTTs needed for the diagnosis of GDM. This algorithm offers a simple, practical, cost-effective and patient-friendly approach for the screening of GDM.

Gestational diabetes: fasting and postprandial glucose as first prenatal screening tests in a high-risk population.

OBJECTIVE: To evaluate the value of fasting (FPG) and 2-hour postprandial (PPG) plasma glucose as screening tests for gestational diabetes mellitus (GDM) in a high-risk population during early pregnancy. STUDY DESIGN: At their first prenatal visit, 708 women underwent FPG and PPG for universal screening for GDM, with the diagnosis confirmed by the 75-g oral glucose tolerance test (World Health Organization criteria). The area under the receiver operating characteristic curve (AUC) was used to analyze the performance of the 2 screening tests. RESULTS: Of 184 (25.9%) women with GDM, 79 (42.9%) were identified before 18 weeks. The AUC for FPG to predict GDM was 0.579 (95% CI 0.531-0.627). Though a threshold of 85 mg/dL achieved minimally acceptable sensitivity, 79.9%, the corresponding specificity remained poor, 27.5%, with a false positive rate (FPR) of 72.5%. The AUC for PPG was 0.717 (95% CI 0.670-0.765); a cutoff of 95 mg/dL achieved a sensitivity of 79.9% and FPR of 53.1%. CONCLUSION: Though GDM could be diagnosed in > 40% women in early pregnancy at their first prenatal visit, the poor specificity and high FPR of FPG and PPG, alone or in combination, make them unsuitable screening tests for GDM.

Implementing the Stockholm Conference hierarchy of objective quality criteria in a routine laboratory.

BACKGROUND: Analytical performance of clinical laboratory testing should be evaluated against objective quality specifications. The Stockholm Conference consensus recommendation states that from a hierarchy of quality models, the highest-ranking model should be used. This study reports the performance of a routine clinical laboratory using these quality recommendations. Quality standards recommended for use in manufacturers' package inserts are also compared against the objective criteria. METHODS: Imprecision of 22 analytes was monitored by analyzing three levels of commercial quality control (QC) material daily over a 6-month period. The performance for each analyte was evaluated against defined quality specifications based on biological variation and the National Cholesterol Education Panel (NCEP) criteria. RESULTS: Overall, objective quality specifications were met by the laboratory for 18/22 (82%) analytes. The performance for analytes not meeting the criteria was assessed against quality targets based on a model lower in the hierarchy, i.e., interlaboratory imprecision data derived from an accredited EQA program. All analytes met these quality targets. When quality targets set by the manufacturer were applied to biological variation and NCEP criteria, results for only 8/22 (36%) analytes met the targets. CONCLUSIONS: Objective quality specifications can be consistently achieved in a routine laboratory. The hierarchy model of the Stockholm Conference should be promoted for global adoption.

Gestational diabetes: relevance of diagnostic criteria and preventive strategies for Type 2 diabetes mellitus.

OBJECTIVE: Women with gestational diabetes mellitus (GDM) are at risk to develop Type 2 diabetes mellitus (DM(2)). The aim of this study was to compare the effect of three international diagnostic criteria on the prevalence of GDM with its implications for prevention of DM(2 )in the population. MATERIALS AND METHODS: One thousand one hundred and seventy-two pregnant women, who underwent the 75-g oral glucose tolerance test for routine, antenatal GDM screening, were classified using the criteria of the American Diabetes Association (ADA), the World Health Organization (WHO) and Australasian Diabetes in Pregnancy Society (ADIPS). The population-attributable risk, (PAR) was used to estimate the proportion of women with DM(2) in the community, who may have been identified much in advance for intervention, by a GDM pregnancy. RESULTS: Using the ADA, WHO and ADPIS criteria, respectively: (a) the prevalence of GDM was 166 (14.2%), 242 (20.6%) and 271 (23.1%) (p < 0.0001); (b) The PAR (95% CI) was 42% (31-52%); 51% (39-62%) and 54% (42-64%). Overall, by all three criteria, 132 (11.3%) women had GDM while 859 (73.3%) were without GDM; the remaining 181 (15.4%) women had classification differences between them. CONCLUSION: The universal acceptance and the ability of the WHO criteria to detect over half the women with DM(2) earlier during pregnancy, makes it ideally suited to identify women with GDM.

Fasting plasma glucose as a screening test for gestational diabetes mellitus.

Although debated, most preeminent expert panels recommend routine screening for gestational diabetes mellitus (GDM). Among the many tests that have been used and evaluated for the screening of GDM, the fasting plasma glucose (FPG) remains very appealing. It is easy to administer, well tolerated, inexpensive, reproducible and patient friendly. However attractive, the FPG has given varied results in different populations and its use as a screening test for GDM remains uncertain. This review will objectively assess the available studies to find the real value of FPG as a screening test for GDM.

Thyroid function abnormalities and antithyroid antibody prevalence in pregnant women at high risk for gestational diabetes mellitus.

Both gestational diabetes mellitus (GDM) and thyroid dysfunction in pregnancy compromise maternal and fetal health. The aim of the present study was to determine the prevalence of abnormal thyroid function and antithyroid antibodies during early pregnancy in a population at high risk for GDM. Serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured in 301 pregnant women who underwent routine 'universal screening' for GDM. The antithyroid peroxidase antibody (antiTPOAb) was also quantified in 255 of these women. GDM was confirmed by a 75-g oral glucose tolerance test using World Health Organization criteria. No statistically significant difference was found between the 80 (26.6%) women with GDM and the 221 (73.4%) women without GDM for any of the thyroid function tests. In the cohort tested for antiTPOAb, the 51 (20.0%) women who were positive for antiTPOAb had higher mean TSH (1.57 +/- 2.49 mIU/l; p < 0.001) than the women negative for antiTPOAb. Seventeen (5.6%) women had low FT4 while 12 (4.0%) women had high TSH; 28 (9.3%) women had low serum TSH, among whom three (1.0%) also had high FT4. The significantly higher prevalence of hypothyroxinemia and antiTPOAb titers than generally reported warrants routine screening for thyroid abnormalities. This screening, which can be effectively and easily incorporated into screening practices already in place for GDM, would result in improved obstetric care.

Gestational diabetes: a reappraisal of HBA1c as a screening test.

BACKGROUND: Recent technological advances have made HBA1c a more standardized and user-friendly test with wide availability. This study evaluated HBA1c as a screening test for gestational diabetes mellitus (GDM) in a high-risk population. METHODS: A total of 442 pregnant women were assessed by HBA1c. Two thresholds were used to "rule in or rule out" GDM, which was confirmed by the "gold-standard" 75-g OGTT (World Health Organization criteria). RESULTS: Eighty-four (19%) women had GDM while 358 (81%) women were normal; there was a complete overlap of the HBA1c histograms of the two populations. The area under receiver operating characteristic curve of HBA1c to detect GDM was 0.54 (95% CI 0.48-0.61). Using a value of <5.5% to rule out GDM; a sensitivity of 82.1% was achieved, with 15 (16.7%) of 90 women below the threshold being false-negatives (NPV = 83.3%). Using a threshold of HBA1c > or = 7.5% to rule-in GDM; the specificity was 95.8% with 15 (71.4%) of 21 patients over the threshold being false-positives (PPV = 28.6%). HBA1c would eliminate the need for an OGTT in 25.1% (111/442) of whom 27% (30/111) women would be misclassified. At any HBA1c threshold with an acceptable sensitivity, the false-positive rate remained high making it necessary for too many healthy women to undergo the confirmatory OGTT. CONCLUSION: Despite all the progress in methodology, HBA1c remains a poor test to screen for GDM.

Gestational diabetes in a high-risk population: using the fasting plasma glucose to simplify the diagnostic algorithm.

OBJECTIVE: To evaluate the value of fasting plasma glucose (FPG) in screening a high-risk population for gestational diabetes mellitus (GDM). STUDY DESIGN: During an 8-month period, 1685 pregnant women underwent the one-step 75 g oral glucose tolerance test (OGTT) as a part of a universal screening program. The receiver operating characteristic (ROC) curve was used to analyze the performance of the FPG. RESULTS: 333 (19.8%) women had GDM (WHO criteria). The area under the ROC curve of FPG to detect GDM was 0.639 (95% CI 0.603-0.674), which reflected the degree of the FPG histogram overlap in women with and without GDM. A FPG threshold of 4.7 mmol/l reached the minimally acceptable sensitivity of 78.1% with a corresponding unacceptable specificity of 32.2%. 508 (31%) women were below this threshold, at a negative predictive value of 85.6%. The FPG at higher thresholds with acceptable specificity had poor sensitivity and positive predictive value to be useful. CONCLUSION: Though the high false positive rate at any FPG threshold with adequate sensitivity makes the FPG an inappropriate test for GDM screening, the FPG has the potential to avoid nearly one-third of the cumbersome OGTTs at the expense of missing one-fifth of pregnant women with milder GDM.

Gestational diabetes: implications of variation in post-partum follow-up criteria.

OBJECTIVE: To compare the recommendations of the American Diabetes Association (ADA) with the World Health Organization (WHO) for evaluating women with gestational diabetes (GDM) after delivery. STUDY DESIGN: During a 5-year period, 549 patients underwent the 2h, 75 g oral glucose tolerance test (OGTT), 4-8 weeks after delivery. They were classified by the criteria of WHO (1985), the ADA [1997, fasting glucose (FPG)] and the revised WHO (1999). RESULTS: The prevalence of diabetes by WHO-1985 and ADA-1997 were similar (8.2% versus 6.6%) but estimates of impaired glucose homeostasis varied widely (15.5% impaired glucose tolerance (IGT) versus 9.3% impaired fasting glucose, respectively). 118 (21.5%) women and 83 (15.1%) women showed a classification discrepancy between ADA-1997 with the WHO-1985 and -1999, respectively. The receiver-operating characteristic (ROC) curve area of the FPG was 0.94 for DM by the OGTT (WHO-1985 criteria) but only 0.59 for IGT by the 2h post-glucose. CONCLUSIONS: The various guidelines for GDM follow-up after delivery, often based on expert opinion, produce similar estimates for diabetes prevalence but widely discordant results for glucose intolerance. Until more uniform evidence-based criteria become available, the various strategies for GDM follow-up will continue to cause confusion in clinical practice.

Evaluation of HbA1C results in an external quality assessment scheme in South Africa.

BACKGROUND: Measuring HbA1c blood levels allows us to assess average glycaemia in individuals during the preceding 6-8 weeks. There is a clear association between increasing risk of complications with higher HbA1c values and a significant risk reduction of the complications with lower HbA1c values. METHODS: The performance of South African laboratories in an External Quality Assurance scheme for HbA1c is reported. CONCLUSIONS: A number of laboratories and methods do not meet the required analytical standards. South African laboratories should adopt measures similar to other regional and national initiatives to significantly improve laboratory performance and bring about harmonization of HbA1c assays.

Biological variation in sweat sodium chloride conductivity.

BACKGROUND: Sweat conductivity, which is equivalent to sweat NaCl concentration, is used as a screening test to identify possible cystic fibrosis (CF) patients. No data exist on the biological variation of this variable and the influence it may have on the interpretation of sweat testing. The aim of this study was to determine the components of biological variation for sweat sodium chloride conductivity and to apply biological variation parameters in the interpretation of sweat conductivity. METHODS: Sweat conductivity was determined once a week for 5 consecutive weeks on 15 healthy volunteers, 20 healthy infants and 20 known CF patients. RESULTS: The analytical coefficient of variation (CV(A)) was 1.15% for the high-level control material, with a value of 123 mmol/L, and 1.32% for the normal-level control material with a value of 40 mmoL/L. The within-subject (CV) and between-subject (CV(G)) biological variations were 12.0% and 30.0%, respectively, for healthy controls; 18% and 20% for healthy infants; and 7.3% and 6.5% for CF patients, respectively. Using the CV(A), CV(G) and CV(I), the 95% reference ranges were determined for the above-mentioned three groups. The calculated 95% ranges for the healthy babies and CF patients were 18-60 mmoL/L and 96-144 mmoL/L. CONCLUSIONS: Our data support a decision level of > 60 mmoL/L for confirmatory CF testing. A lower decision level will result in an unacceptable high rate of unnecessary confirmation testing.