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Objective To analyze the status of quality indicators(QI) on specimen acceptability and establish preliminary qual ity specification.Methods Web based External Quality Assessment system was used to collect data of laboratories partici pated in "Medical quality control indicators in clinical laboratory" from 2015 to 2017,including once in 2015 and 2017 and twice in 2016.Rate and sigma scales were used to evaluate incorrect sample type,incorrect sample container,incorrect fill level and anticoagulant sample clotted.The 25th percentile (P25) and 75th percentile (P75) of the distribution of each QI were employed to establish the high,medium and low specification.Results 5 346,7 593,5 950 and 6 874 laboratories sub mitted the survey results respectively.The P50 of biochemistry (except incorrect fill level),immunology and microbiology reach to 6σ.The P50 of clinical laboratory is 4 to 6σ except for incorrect sample container.There is no significant change of the continuous survey results.Based on results in 2017 to establish the quality specification,the P25 and P75 of the four QIs is 0 and 0.084 4 ％,0 and 0.047 6 ％,0 and 0.114 2 ％,0 and 0.078 4 ％,respectively.Conclusion According to the results of the survey,most laboratories had a faire performance in biochemistry,immunology and microbiology,and clinical laboratory needs to be strengthened.Laboratories should strengthen the laboratory information system construction to ensure the actual and reliable data collection,and make a long time monitoring to achieve a better quality.
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Glucose meters often have similar performance when compared by error grid analysis.This is one reason that other statistics such as mean absolute relative deviation (MARD) are used to further differentiate performance.The problem with MARD is that too much information is lost.But additional information is available within the A zone of an error grid by using the Taguchi loss function.Applying the Taguchi loss function gives each glucose meter difference from reference a value ranging from 0 (no error) to 1 (error reaches the A zone limit).Values are averaged over all data which provides an indication of risk of an incorrect medical decision.This allows one to differentiate glucose meter performance for the common case where meters have a high percentage of values in the A zone and no values beyond the B zone.Examples are provided using simulated data.
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In the last few years much progress has been made in raising the awareness of laboratory medicine professionals a bout the effectiveness of quality indicators (QIs) in monitoring,and improving upon,performances in the extra-analytical phases of the total testing process (TTP).An effective system for management of QIs includes the implementation of an internal assessment system and participation in inter-laboratory comparison.A well-designed internal assessment system allows the identification of critical activities and their systematic monitoring.Active participation in inter-laboratory comparison provides information on the performance level of one laboratory with respect to that of other participating laboratories.In order to guarantee the use of appropriate QIs and facilitate their implementation,many laboratories have adopted the Model of Quality Indicators (MQI) proposed by Working Group "Laboratory Errors and Patient Safety" (WG-LEPS) of IFCC,since 2008,which is the result of international consensus and continuous experimentation,and updating to meet new,con stantly emerging needs.Data from participating laboratories are collected monthly and reports describing the statistical results and evaluating laboratory data,utilizing the Six Sigma metric,issued regularly.Although the results demonstrate that the processes need to be improved upon,overall the comparison with data collected in 2014 shows a general stability of quality levels and that an improvement has been achieved over time for some activities.The continuous monitoring of QI dataallows identification all possible improvements,thus highlighting the value of participation in the inter-laboratory program proposed by WGLEPS.The active participation of numerous laboratories will guarantee an ever more significant State-of-the-Art,promote the reduction of errors and improve quality of the TTP,especially the extra-analytical quality,thus guaranteeing patient safety.
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<p><b>Background</b>Measuring total serum calcium is important for the diagnosis of diseases. Currently, results from commercial kits for calcium measurement are variable. Generally, the performance of serum calcium measurements is monitored by external quality assessment (EQA) or proficiency testing schemes. However, the commutability of the EQA samples and calibrators is often unknown, which limits the effectiveness of EQA schemes. The aim of this study was to evaluate the bias of serum calcium measurements and the commutability of processed materials.</p><p><b>Methods</b>Inductively coupled plasma mass spectrometry was applied as a comparative method, and 14 routine methods were chosen as test methods. Forty-eight serum samples from individual patients and 25 processed materials were quantified. A scatter plot was generated from patient samples, and 95% prediction intervals were calculated to evaluate the commutability of the processed materials and measurement bias at three concentration levels was used to determine the accuracy of routine assays.</p><p><b>Results</b>All assays showed high precision (total coefficient of variation [CV] <2.26%) and correlation coefficients (r > 0.99). For all assays, the mean bias for the 48 patient samples ranged from -0.13 mmol/L to 0.00 mmol/L (-5.61-0.01%), and the ranges for the three concentrations were -0.10-0.04 mmol/L (-5.71-2.35%), -0.14--0.01 mmol/L (-5.80--0.30%), and -0.19-0.04 mmol/L (-6.24-1.22%). The EQA samples, calibrators, and animal sera exhibited matrix effects in some assays; human serum pools were commutable in all assays; certificate reference materials were commutable in most assays, and only GBW09152 exhibited a matrix effect in one assay; and aqueous reference materials exhibited matrix effects in most assays.</p><p><b>Conclusions</b>Biases for most assays were within the acceptable range, although the accuracy of some assays needs improvement. Human serum pools prepared from patient samples were commutable, and the other tested materials exhibited a matrix effect.</p>
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<p><b>BACKGROUND</b>Hemoglobin A1c (HbA1c) measurement is of great value for the diagnosis and monitoring of diabetes. Many manufacturers have developed various experiments to determine the HbA1c concentration. However, the longitudinal use of these tests requires strict quality management. This study aimed to analyze the quality of HbA1c measurement systems in China using six sigma techniques to help improve their performances.</p><p><b>METHODS</b>A total of 135 laboratories were involved in this investigation in 2015. Bias values and coefficients of variation were collected from an HbA1c trueness verification external quality assessment program and an internal quality control program organized by the National Center of Clinical Laboratories in China. The sigma (σ) values and the quality goal index (QGI) were used to evaluate the performances of different groups, which were divided according to principles and instruments.</p><p><b>RESULTS</b>The majority of participants (88, 65.2%) were scored as "improvement needed (σ < 3)", suggesting that the laboratories needed to improve their measurement performance. Only 8.2% (11/135) of the laboratories were scored as "world class (σ ≥ 6)". Among all the 88 laboratories whose σ values were below 3, 52 (59.1%) and 23 (26.1%) laboratories needed to improve measurement precision (QGI <8.0) and trueness (QGI >1.2), respectively; the remaining laboratories (13, 14.8%) needed to improve both measurement precision and trueness. In addition, 16.1% (5/31) and 15.0% (3/20) of the laboratories in "TOSOH" and "ARKRAY" groups, respectively, were scored as "world class", whereas none of the laboratories in "BIO-RAD" group were scored as "world class".</p><p><b>CONCLUSIONS</b>This study indicated that, although participating laboratories were laboratories with better performance in China, the performances were still unsatisfactory. Actions should be taken to improve HbA1c measurement performance before we can include HbA1c assays in diabetes diagnosis in China.</p>
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Humans , China , Diabetes Mellitus , Blood , Metabolism , Glycated Hemoglobin , Metabolism , Quality Assurance, Health Care , MethodsABSTRACT
Objective To develop a new isotope dilution gas chromatography mass spectrometry method (ID/GC/MS) for the measurement of serum cholesterol.Methods Serum was mixed with an isotope labeled internal standard ([3,4-~(13)C]-cholesterol) and treated with alcoholic sodium hydroxide to hydrolyze cholesterol ester to cholesterol.Cholesterol and internal standard was extracted and derived by N, O-Bis(trimethylsilyl) trifluoroacetamide to trimethylsilyl ethers.The derivation products were analyzed by capillary column GC combined with electron impact MS using scan and selected ion monitor (SIM) modes. Signals of cholesterol internal standard were corrected for the contributions from cholesterol and the signal ratio of cholesterol to internal standard for the calibrators were linearly regressed against cholesterol concentrations.The resulted regression equation was used for the calculation of serum cholesterol concentrations.Results The new ID/GC/MS method showed a mean within-run coefficient variance (CV) of 0.04%-0.81%.Comparison with two levels of standard reference material (SRM1951a) of National Institute of Standards and Technology (NIST) displayed a bias of 0.19% and 0.90% respectively.Conclusion A time-gaining ID/MS method has been established that is highly precise and accurate and can be used for the measurement of serum cholesterol.