Gurdeep S. Dhatt

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 ≥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: 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.

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.

Novel test and its automation for the determination of erythrocyte acetylcholinesterase and its application to organophosphate exposure

BACKGROUND Because of the lack of a problem-free, reliable method for determination of erythrocyte acetylcholinesterase (AChE), we developed a simple kinetic method, which we found to be both reliable and suitable for automation in the routine clinical laboratory. METHODS Acetylthiocholine, used as substrate, is hydrolysed by acetylcholinesterase to yield acetate and thiocholine. Thiocholine reacts with dichlorophenolindophenol, a blue coloured compound, which is reduced to a colourless product, producing a linear decrease in absorption at 606 nm. If required, this assay can also be run at 600 nm with equally acceptable results. RESULTS The method was automated on the Synchron LX20 multianalyser (Beckman Instruments) and blood samples of 80 patients with clinically symptomatic organophosphate poisoning and 153 normal controls were evaluated. Acetylcholinesterase values were in the range of 0-14 UgHb(-1) in cases of organophosphate poisoning, in contrast with normal controls, who had AChE values of 24.4--37.9 UgHb(-1). No overlap was found between AChE values of controls and poisoned cases. Intra- and inter-assay coefficients of variation were 1.68 and 3.71%, respectively. CONCLUSION The method we propose for measurement of AChE was found to be simple, reliable and easily automatable in the routine clinical laboratory.

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.

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 (CVA) 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 (CVI) and between-subject (CVG) 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 CVA, CVG and CVI, 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.

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.

Patient safety: patient identification wristband errors.

Gurdeep S. Dhatt*, Hassan Abu Damir, Steven Matarelli, Krishnan Sankaranarayanan and David M. James 1 Department of Laboratory Medicine, Tawam Hospital, Al Ain, United Arab Emirates 2 Chief Operating Officer, Tawam Hospital, Al Ain, United Arab Emirates 3 Department of Performance Innovation, Tawam Hospital, Al Ain, United Arab Emirates 4 Department of Clinical Services, Tawam Hospital, Al Ain, United Arab Emirates

Impact of a satellite laboratory on turnaround times for the emergency department.

Abstract Background: Prolonged laboratory turnaround time (TAT) contributes to prolonged length of stay in emergency departments (EDs). The TAT of laboratory test results is a common key performance indicator by which clinicians and regulatory bodies evaluate laboratory performance. Establishing satellite laboratories in EDs staffed by laboratory technologists is one approach towards reducing TAT. Methods: TAT data were collected for three time intervals: (a) sampling time to time samples received in the laboratory (transportation time), (b) sample received in the laboratory until results were available for viewing on the laboratory information system monitor or collection by ED staff (within laboratory TAT), and (c) sampling to availability of results (total TAT, e.g., a+b). The target was to achieve a median within laboratory TAT of 45 min for samples received from the ED. Results: The median transportation times for samples to be delivered to the central and satellite laboratory were 22 min and 1 min, respectively (p<0.0001). The median within laboratory TATs were 45 [95% confidence interval (CI) 43–49] and 34 (95% CI 33–35) min for the central and satellite laboratories, respectively (p<0.001). Conclusions: A satellite laboratory in the ED can significantly reduce laboratory TAT. Clin Chem Lab Med 2008;46:1464–7.

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.