Background： 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 measurem...Background： 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. Methods： 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. Results： 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 mmoUL （-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. Conclusions： 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.展开更多
Background： Hemoglobin A 1 c （HbA1 c） measurement is of great value for the diagnosis and monitoring of diabetes. Many manufacturers have developed various experiments to determine the HbAlc concentration. However,...Background： Hemoglobin A 1 c （HbA1 c） measurement is of great value for the diagnosis and monitoring of diabetes. Many manufacturers have developed various experiments to determine the HbAlc concentration. However, the longitudinal use of these tests requires strict quality management. This study aimed to analyze the quality of HbAlc measurement systems in China using six sigma techniques to help improve their performances. Methods： A total of 135 laboratories were involved in this investigation in 2015. Bias values and coefficients of variation were collected from an HbA 1 c 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. Results： 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 ＂TO SOH＂ and ＂ARKRAY＂ groups, respectively, were scored as ＂world class＂, whereas none of the laboratories in ＂BIO-RAD＂ group were scored as ＂world class＂. Conclusions： 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 HbAlc measurement performance before we can include HbAlc assays in diabetes diagnosis in China.展开更多
文摘Background： 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. Methods： 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. Results： 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 mmoUL （-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. Conclusions： 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.
文摘Background： Hemoglobin A 1 c （HbA1 c） measurement is of great value for the diagnosis and monitoring of diabetes. Many manufacturers have developed various experiments to determine the HbAlc concentration. However, the longitudinal use of these tests requires strict quality management. This study aimed to analyze the quality of HbAlc measurement systems in China using six sigma techniques to help improve their performances. Methods： A total of 135 laboratories were involved in this investigation in 2015. Bias values and coefficients of variation were collected from an HbA 1 c 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. Results： 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 ＂TO SOH＂ and ＂ARKRAY＂ groups, respectively, were scored as ＂world class＂, whereas none of the laboratories in ＂BIO-RAD＂ group were scored as ＂world class＂. Conclusions： 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 HbAlc measurement performance before we can include HbAlc assays in diabetes diagnosis in China.
