***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old . Such investigations are often analysed inappropriately , notably by using correlation coefficients . The use of correlation is misleading . An alternative approach , based on graphical techniques and simple calculations , is described , together with the relation between this analysis and the assessment of repeatability The recommended method for assessing long-term blood glucose control in diabetic patients is the measurement of glycated haemoglobin ( Hb ) . The Ames DCA 2000 system for assaying glycated Hb uses an immunoassay with a monoclonal antibody specific for an aminoacid sequence within the HblAc molecule . This study compared the performance of the DCA 2000 system for HblAc measurement with that of high-performance liquid chromatography ( HPLC ) . A total of 1.016 insulin-dependent and non-insulin-dependent diabetic patients from 5 outpatient clinics took part . The correlation coefficients between DCA 2000 and HPLC data ranged between 0.94 and 0.98 , depending on site . The mean variations and 95 % confidence intervals for the differences between the results for each sample were : site A 0.172 ( -1.186 to 1.53 ) , site B -0.275 ( -1.317 to 0.767 ) , site C -0.146 ( -0.868 to 0.576 ) , site D -0.088 ( -0.864 to 0.688 ) , and site E -0.251 ( -1.099 to 0.597 ) . The sensitivity of the DCA 2000 assay ranged between 80 and 94 % , and the specificity between 88 and 100 % , depending on site . For pooled results , the correlation coefficient assayed by the two methods was 0.95 . The mean variation was -0.116 and the 95 % confidence interval -1.23 to 0.998 . The sensitivity of DCA 2000 was 91 % , and the specificity 94 % . DCA tended to underestimate HbAlc slightly as compared to HPLC . This study confirms the reliability of DCA 2000 for measuring glycated Hb . The system is easy to use and provides valuable information for the care of the diabetic patients BACKGROUND Glycosylated hemoglobin evaluation is very important for assessing the control of diabetes . Since the use of point-of-care ( POC ) devices for monitoring HbA1c is increasing , it is important to determine how these devices compare in relation to instrumentation used in the central laboratory ( CL ) . METHODS Eighty-eight r and omly selected sample s previously analyzed using the Bio-Rad Variant ™ II Hemoglobin Testing System were run on three POC Analyzers ( Siemens DCA Vantage ™ Analyzer , Axis-Shield Afinion ™ AS100 Analyzer , and Bio-Rad In2it ™ Analyzer ) . RESULTS All POC instruments showed good correlation to the CL method ( R(2)>0.95 for all methods ) . HbA1c levels obtained using Variant II ( mean=7.9 ; 95 % CI=7.5 - 8.3 % ) and In2it ( mean=7.9 ; 95 % C.I.=7.5 - 8.2 % ) instruments were found to have no statistical mean difference ( p=0.21 ) , while the values obtained using DCA Vantage ( mean=7.2 % C.I.=6.9 - 7.5 % ) and Afinion ( mean=7.3 % C.I.=7.0 - 7.6 % ) instruments were different ( p<0.001 ) from those of the CL method . The Afinion and DCA Vantage instruments increasingly underestimated the HbA1c compared to the CL as the HbA1c values increased . These differences were even more striking when the estimated average glucose is calculated . CONCLUSIONS Despite significant variation of results among the POC instruments evaluated relative to the CL method and pending resolution of HbA1c st and ardization issues , we conclude that all of the POC instruments can be used for HbA1c determination if clinicians are given instrument specific reference ranges Abstract Objective : To determine the relation between exposure to glycaemia over time and the risk of macrovascular or microvascular complications in patients with type 2 diabetes . Design : Prospect i ve observational study . Setting : 23 hospital based clinics in Engl and , Scotl and , and Northern Irel and . Participants : 4585 white , Asian Indian , and Afro-Caribbean UKPDS patients , whether r and omised or not to treatment , were included in analyses of incidence ; of these , 3642 were included in analyses of relative risk . Outcome measures : Primary predefined aggregate clinical outcomes : any end point or deaths related to diabetes and all cause mortality . Secondary aggregate outcomes : myocardial infa rct ion , stroke , amputation ( including death from peripheral vascular disease ) , and microvascular disease ( predominantly retinal photo-coagulation ) . Single end points : non-fatal heart failure and cataract extraction . Risk reduction associated with a 1 % reduction in up date d mean HbA1c adjusted for possible confounders at diagnosis of diabetes . Results : The incidence of clinical complications was significantly associated with glycaemia . Each 1 % reduction in up date d mean HbA1c was associated with reductions in risk of 21 % for any end point related to diabetes ( 95 % confidence interval 17 % to 24 % , P<0.0001 ) , 21 % for deaths related to diabetes ( 15 % to 27 % , P<0.0001 ) , 14 % for myocardial infa rct ion ( 8 % to 21 % , P<0.0001 ) , and 37 % for microvascular complications ( 33 % to 41 % , P<0.0001 ) . No threshold of risk was observed for any end point . Conclusions : In patients with type 2 diabetes the risk of diabetic complications was strongly associated with previous hyperglycaemia . Any reduction in HbA1c is likely to reduce the risk of complications , with the lowest risk being in those with HbA1c values in the normal range ( < 6.0 % ) OBJECTIVE Accurate and reliable HbA1c results can be obtained at the time of the office visit by using benchtop analyzers . We tested the hypothesis that immediately available HbA1c results could improve glycemic control by changing physician or patient behavior or both . RESEARCH DESIGN AND METHODS A r and omized controlled trial was conducted in 201 type 1 and insulin-treated type 2 diabetic patients attending an academic diabetes center .  HbA1c levels , changes in insulin therapy , and use of health care re sources  were assessed during a 12-month follow-up period . RESULTS HbA1c levels decreased significantly at 6 and 12 months in the immediate assay group ( -0.57 + /- 1.44 and -0.40 + /- 1.65 % , respectively ; P < 0.01 ) but did not change in the control group ( -0.11 + /- 0.79 and -0.19 + /- 1.16 % , respectively ; NS ) . The changes were similar for both type 1 and type 2 diabetic patients . There were no differences in the rates of hypoglycemic events or use of health care re sources . CONCLUSIONS In the setting of a controlled r and omized trial , the immediate feedback of HbA1c results at the time of patient encounters result ed in a significant improvement of glycemic control at 6-month follow-up and persisted for the 12-month study . The introduction of this assay was positively received by both patients and physicians Background : Glycohemoglobin A1c ( HbAlc ) is a universally accepted tool for glycemic control . Portable HbAlc devices for use in physicians ' offices are desirable because they provide immediate results that physicians can share with their patients . This has been shown to enhance self-management in patients with diabetes . We undertook this study to evaluate the accuracy and precision of a recently introduced device , the AlcNow ® InView ™ capillary monitor . Method : Previously tested EDTA-preserved whole blood sample s from our laboratory pool were preselected based on the results of HbAlc to cover a range from 4 to 13 % . HbAlc was then measured using an AlcNow InView capillary monitor . Blinded aliquots of these sample s were then sent to a National Glycohemoglobin St and ardization Program (NGSP)-certified reference laboratory for comparison . One sample with a laboratory HbAlc result of 9.2 % was measured with the InView device nine successive times to assess the device precision . The consistency between the measurement of HbAlc measured by the reference laboratory and the AlcNow InView device was analyzed via linear regression . Results : Thirty-five sample s were tested .  The correlation between HbAlc measured by the InView device and the reference laboratory , as well as our own laboratory , was 0.96 . The coefficient of variation was 2.7l ° % . Conclusions : Results of this study confirm the accuracy and precision of the InView capillary HbAlc monitor . However , the feasibility , reproducibility , and cost-effectiveness of this promising device in the real-life setting s of physicians ' offices must be verified by prospect i ve clinical studies Background : The measurement of haemoglobin A1c(HbA1c ) by high-performance liquid chromatography ( HPLC ) is generally deemed unsuitable for point of care testing ( POCT ) due to its complexity and extended turnaround times ( TAT ) . The aim of this project was to evaluate two new HPLC instruments , the Bio-Rad D10 and the Primus PDQ , as POCT instruments compared with Bayer 's DCA2000 HbA1c immunoassay analyser in our paediatric diabetes clinic . Methods : A total of 228 sample s were analysed , of which 160 analyses were performed in our paediatric diabetes clinic .  HbA1c results were compared by the Passing-Bablok agreement test , the Bl and -Altman difference analysis , within- and between-run imprecision , and TAT . Results : : The agreement test and difference analysis showed a correlation of r 2=0.96 and a mean HbA1c difference of < 0.1 % between the three analysers . The PDQ and the D10 achieved the within-run target coefficient of variation ( CV ) of < 2 % at an HbA1c of 7.5 % . Between-run imprecision at an HbA1c of 10.8 % produced CV of 3.5 % , 2.4 % and 1.6 % for the D10 , DCA2000 and PDQ , respectively . TAT studies confirmed that the PDQ was substantially faster than the DCA2000 and D10 . Conclusions : The PDQ had the shortest TAT , afforded r and om access and exhibited acceptable imprecision , and hence is the preferred instrument for our POCT environment Rapid in clinic measurement of glycated hemoglogin ( HbA1c ) allows to determine the level of metabolic control within a few minutes on capillary blood . We have evaluated the new DCA Vantage ( Siemens ) based on an immunological technique , replacing the DCA 2000 + ( Siemens ) . The study included 120 unselected young type 1 diabetic patients , with different degrees of metabolic control . The DCA Vantage was compared with the HPLC system ( Menarini HA 8160 ) whose deviation from the DCCT was < 0.1 % across the clinical range . The mean underestimation of the DCA Vantage was -0.40 % . The agreement limits ( + /- 1.96 SD ) were between 0.14 % and -0.93 % ; this means + /- 0.53 % around -0.40 % . In conclusion , the DCA Vantage underestimates HbA1c levels ; however it met the acceptance criteria of having a coefficient of variation < 3 % OBJECTIVE Failure to meet goals for glycemic control in primary care setting s may be due in part to lack of information critical to guide intensification of therapy . Our objective is to determine whether rapid-turnaround A1c availability would improve intensification of diabetes therapy and reduce A1c levels in patients with type 2 diabetes . RESEARCH DESIGN AND METHODS In this prospect i ve controlled trial , A1c was determined on capillary glucose sample s and made available to providers , either during ( " rapid " ) or after ( " routine " ) the patient visit . Frequency of intensification of pharmacological diabetes therapy in inadequately controlled patients and A1c levels were assessed at baseline and after follow-up . RESULTS We recruited 597 subjects . Patients were 79 % female and 96 % African American , with average age of 61 years , duration of diabetes 10 years , BMI 33 kg/m(2 ) , and A1c 8.5 % . The rapid and routine groups had similar clinical demographics . Rapid A1c availability result ed in more frequent intensification of therapy when A1c was > /=7.0 % at the baseline visit ( 51 vs. 32 % of patients , P = 0.01 ) , particularly when A1c was > 8.0 % and /or r and om glucose was in the 8.4 - 14.4 mmol/l range ( 151 - 250 mg/dl ) . In 275 patients with two follow-up visits , A1c fell significantly in the rapid group ( from 8.4 to 
    Output:
    
There was no difference in bias between clinical or laboratory operators in two devices .
Conclusions : This is the first meta- analysis to directly compare performance of POC HbA1c devices .
Use of a device with a mean negative bias compared to a laboratory method may lead to higher levels of glycemia and a lower risk of hypoglycaemia .