scholarly journals Establishment of glycated albumin unit conversion equation from the standardized value (mmol/mol) to the routinely used value (%)

2018 ◽  
Vol 56 (2) ◽  
pp. 204-209 ◽  
Author(s):  
Asako Sato ◽  
Sayo Yada ◽  
Emiko Hosoba ◽  
Hiroko Kanno ◽  
Hitomi Miura
Keyword(s):  
Clinical Chemistry ◽  
Glycated Albumin ◽  
Reference Method ◽  
Enzymatic Method ◽  
Easy Method ◽  
Standard Material ◽  
Basic Performance ◽  
Conversion Formula ◽  
Unit Conversion ◽  
Conversion Equation

Background To promote glycated albumin standardization, the Committee on Diabetes Mellitus Indices, Japan Society of Clinical Chemistry published the recommended reference method and is supplying the reference standard material (JCCRM 611). In this study, we evaluated the basic performance of ‘standardized enzymatic method’ that is traceable to JCCRM 611 and established a unit conversion formula from standardized glycated albumin value (mmol/mol) to the routinely used glycated albumin value (%). Methods To evaluate the accuracy and within-run reproducibility of the ‘standardized enzymatic method’, JCCRM 611 was measured 20 times. To establish the unit conversion formula, serum specimens with known HbA1c concentrations were collected, and their glycated albumin (%) and glycated albumin (mmol/mol) were measured. Results The accuracy of glycated albumin value of the ‘standardized enzymatic method’ was 100.8–103.0%. The within-run reproducibility CV (coefficient of variation, %) of glycated albumin value was 0.6–0.9%. In total, 240 serum specimens were collected, and the distribution of their HbA1c values was HbA1c ≤ 4.9% ( n = 23), 5.0–5.9% ( n = 50), 6.0–6.9%, ( n = 44), 7.0–7.9% ( n = 40), 8.0–8.9% ( n = 37) and ≥9.0% ( n = 46). The unit conversion equation was defined as: GA (%) = 0.05652 × GA (mmol/mol)–0.4217 ( r = 0.999). Glycated albumin (%) calculated by the equation was in close agreement (96.6–104.2%) with the actual measured glycated albumin (%). Conclusions The glycated albumin unit conversion formula was established from mmol/mol to %. This formula provides an easy method to convert the unit and is expected to be useful for the standardization of glycated albumin measurement.

scholarly journals Basic Performance of an Enzymatic Method for Glycated Albumin and Reference Range Determination

2011 ◽  
Vol 5 (6) ◽  
pp. 1455-1462 ◽  
Author(s):  
Takuji Kohzuma ◽  
Tamotsu Yamamoto ◽  
Yumiko Uematsu ◽  
Zak K. Shihabi ◽  
Barry I. Freedman
Keyword(s):  
Reference Range ◽  
Glycated Albumin ◽  
Enzymatic Method ◽  
Basic Performance ◽  
Range Determination

scholarly journals Between-Country Comparability of Clinical Chemistry Results: An International Quality Assessment Survey of 17 Analytes in Six European Countries through Existing National Schemes

1993 ◽  
Vol 30 (3) ◽  
pp. 304-314 ◽  
Author(s):  
R T P Jansen ◽  
D G Bullock ◽  
A Vassault ◽  
H Baadenhuijsen ◽  
A De Leenheer ◽  
...  
Keyword(s):  
The Netherlands ◽  
Quality Assessment ◽  
Mutual Recognition ◽  
Clinical Chemistry ◽  
Reference Method ◽  
European Countries ◽  
Mean Values ◽  
Related Data ◽  
Standard Deviations ◽  
The Uk

Two lyophilized control sera were distributed through seven national external quality assessment schemes in six European countries—Belgium, Switzerland, France, The Netherlands, Sweden and the United Kingdom—participated in the study. The results for 17 routine analytes were obtained from almost 5000 laboratories for the two sera. The organizers of the schemes were asked to process the results according to a common outlier removal procedure, and submit method-related data if available. The two sera were also distributed through the external/internal scheme of The Netherlands, and the within-laboratory standard deviations calculated in this scheme have been used in a scaling procedure for the external mean values and between-laboratory standard deviations of the participating countries. The results show remarkable agreement in the national mean values for practically all analytes, but considerable differences in the between-laboratory variation. Data from comparable method groups was obtained for 12 analytes from Belgium, France, The Netherlands and the UK. Though revealing some specific differences between methods and countries, the method-related data are generally in agreement with the all-method data. In this study reference method values were only available for cholesterol. The high degree of agreement found suggests, however, that mutual recognition of all-method mean values in national schemes could be acceptable, especially for analytes for which reliable reference methods are not available. The major element of variation is between-laboratory rather than between-country.

scholarly journals Pre-analytical quality control in hemostasis laboratories: visual evaluation of hemolysis index alone may cause unnecessary sample rejection

2019 ◽  
Vol 43 (2) ◽  
pp. 67-76
Author(s):  
Simona Storti ◽  
Elena Battipaglia ◽  
Maria Serena Parri ◽  
Andrea Ripoli ◽  
Stefania Lombardi ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Visual Inspection ◽  
Clinical Chemistry ◽  
Linear Regression Analysis ◽  
Reference Method ◽  
Analytical Performance ◽  
Visual Evaluation ◽  
Automated Method ◽  
Visual Index

Abstract Background Visual inspection is the most widespread method for evaluating sample hemolysis in hemostasis laboratories. The hemolysis index (HI) was determined visually (visual index, VI) and measured on an ACL TOP 750 (IL Werfen) system with a hemolysis-icterus-lipemia index (HIL) module. These values were compared with those measured on clinical chemistry systems Unicel DXC600 and AU680 and with quantitation of free-hemoglobin (Hb) performed by a spectrophotometric measurement method (SMM). Methods The HI was measured in 356 sodium citrate plasma samples, 306 of which were visibly hemolyzed to varying degrees and 50 were not hemolyzed. The analytical performance of each method was evaluated. Results Linear regression analysis, calculated between SMM and the other systems in the study, returned coefficients of determination r2 = 0.853 (AU680), r2 = 0.893 (DXC600) and r2 = 0.917 (ACL TOP 750). An r2 = 0.648 was obtained for linear regression analysis between VI and ACL TOP 750. In addition, ACL TOP 750 showed an excellent correlation in multivariate analysis (r2 = 0.958), showing good sensitivity (0.939) and specificity (0.934) and a diagnostic accuracy of 94%. By comparison, DXC600 and AU680 showed coefficients of determination of 0.945 and 0.923, respectively. A cut-off was set at 0.15 g/L free-Hb, as determined by the automated method, such that any hemostasis samples measuring above this threshold should not be analyzed. Based on this criterion, samples were classified as accepted or rejected, and the number of samples discarded during VI or ACL TOP 750 measurements was compared. Conclusions This study confirmed that hemostasis laboratories should consider introducing an objective, automated and standardized method to check samples for hemolysis. By relying solely on visual inspection, up to 50% of samples could be unnecessarily rejected. The ACL TOP 750 system demonstrated a satisfactory analytical performance, giving results comparable to those of the reference method.

scholarly journals Evaluation of Quality Control Methods for Foot-And-Mouth Disease Vaccines by High-Performance Liquid Chromatography

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 194
Author(s):  
Mun-Hyeon Kim ◽  
Seon-Jong Yun ◽  
Yeon-Hee Kim ◽  
Hyang-Sim Lee ◽  
Ji-Yeon Kim ◽  
...  
Keyword(s):  
Quality Control ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Foot And Mouth Disease ◽  
Reference Method ◽  
Mouth Disease ◽  
Control Measures ◽  
Standard Material ◽  
Foot And Mouth

Foot-and-mouth disease (FMD) is considered one of the highly contagious viral infections affecting livestock. In Korea, an FMD vaccination policy has been implemented nationwide since 2010 for the prevention and control of FMD. Since the vaccines are imported from various countries, standardized quality control measures are critical. In this study, we aimed to validate a high-performance liquid chromatography (HPLC) device in the Animal and Plant Quarantine Agency lab and identify an appropriate FMD vaccine pretreatment method for HPLC—a simple, reliable, and practical method to measure antigen content. Based on the analyses of specificity, linearity, accuracy, repeatability, intermediate precision, limits of detection, and limits of quantification using FMD standard samples, we validated the method using a standard material. Overall, we confirmed that the HPLC technique is effective for the quantitative assessment of the FMD virus 146S antigen in Korea. Using commercial FMD vaccines, we evaluated three separation methods and identified the method using n-pentanol and trichloroethylene as optimal for HPLC analysis. Our HPLC method was effective for the analytical detection of the antigen content in FMD vaccine, and it may be useful as a reference method for national lot-release testing.

scholarly journals IFCC Reference System for Measurement of Hemoglobin A1c in Human Blood and the National Standardization Schemes in the United States, Japan, and Sweden: A Method-Comparison Study

2004 ◽  
Vol 50 (1) ◽  
pp. 166-174 ◽  
Author(s):  
Wieland Hoelzel ◽  
Cas Weykamp ◽  
Jan-Olof Jeppsson ◽  
Kor Miedema ◽  
John R Barr ◽  
...  
Keyword(s):  
Reference System ◽  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
The United States ◽  
Reference Laboratory ◽  
Regression Equations ◽  
National Programs ◽  
Method Comparison Study ◽  
The Relationship

Abstract Background: The national programs for the harmonization of hemoglobin (Hb)A1c measurements in the US [National Glycohemoglobin Standardization Program (NGSP)], Japan [Japanese Diabetes Society (JDS)/Japanese Society of Clinical Chemistry (JSCC)], and Sweden are based on different designated comparison methods (DCMs). The future basis for international standardization will be the reference system developed by the IFCC Working Group on HbA1c Standardization. The aim of the present study was to determine the relationships between the IFCC Reference Method (RM) and the DCMs. Methods: Four method-comparison studies were performed in 2001–2003. In each study five to eight pooled blood samples were measured by 11 reference laboratories of the IFCC Network of Reference Laboratories, 9 Secondary Reference Laboratories of the NGSP, 3 reference laboratories of the JDS/JSCC program, and a Swedish reference laboratory. Regression equations were determined for the relationship between the IFCC RM and each of the DCMs. Results: Significant differences were observed between the HbA1c results of the IFCC RM and those of the DCMs. Significant differences were also demonstrated between the three DCMs. However, in all cases the relationship of the DCMs with the RM were linear. There were no statistically significant differences between the regression equations calculated for each of the four studies; therefore, the results could be combined. The relationship is described by the following regression equations: NGSP-HbA1c = 0.915(IFCC-HbA1c) + 2.15% (r2 = 0.998); JDS/JSCC-HbA1c = 0.927(IFCC-HbA1c) + 1.73% (r2 = 0.997); Swedish-HbA1c = 0.989(IFCC-HbA1c) + 0.88% (r2 = 0.996). Conclusion: There is a firm and reproducible link between the IFCC RM and DCM HbA1c values.

Comparison of the International Federation of Clinical Chemistry and Japan Diabetes Society reference methods for conversion to the National Glycohemoglobin Standardization Program values

2019 ◽  
Vol 56 (4) ◽  
pp. 508-514
Author(s):  
Katsuyuki Nakajima ◽  
Isao Koyama ◽  
Makoto Watanabe ◽  
Masakazu Nakamura ◽  
Yoshihiro Miyamoto ◽  
...  
Keyword(s):  
Clinical Chemistry ◽  
Method Comparison ◽  
Reference Method ◽  
International Federation ◽  
Haemoglobin A1c ◽  
Regression Equations ◽  
National Programmes ◽  
The Us ◽  
Level 1 ◽  
The Relationship

Background The national programmes for the harmonization of haemoglobin A1c measurement in the US and Japan are based on differently designated comparison methods. The future basis for international standardization is expected to be the reference system developed by the International Federation of Clinical Chemistry (IFCC) Working Group on haemoglobin A1c Standardization. The aim of the present study is to compare the relationship between the IFCC reference method (RM) and Japanese Diabetes Society (JDS) RM used for the conversion to the National Glycohemoglobin Standardization Program (NGSP) values. Methods Three different method-comparison studies were performed. All blood samples were measured at the National Cerebral and Cardiovascular Centers (Lipid Reference Laboratories) that serve as Level 1 reference laboratories of the NGSP Network. Regression equations were calculated for the IFCC RM and JDS RM for the conversion to NGSP values. Results Differences were found between the haemoglobin A1c values of the IFCC RM and those of JDS. However, in all cases, the relationships of the IFCC RM and JDS RM were linear and commutable. The relationship is described by the following regression equations: NGSP-HbA1c = 0.915(IFCC-HbA1c) + 2.15% (r2 = 0.998); JDS/JSCC-HbA1c = 0.927(IFCC-HbA1c) + 1.73% (r2 = 0.997). Conclusion There is a firm and reproducible link between the IFCC and JDS-HbA1c values. However, the values calibrated by JDS RM were consistently and significantly higher than the IFCC values (0.1–0.2%) when used for conversion to the NGSP values.

An enzymic assay for the specific determination of methanol in serum.

1987 ◽  
Vol 33 (12) ◽  
pp. 2204-2208 ◽  
Author(s):  
B Vinet
Keyword(s):  
Clinical Chemistry ◽  
Alcohol Oxidase ◽  
Chemistry Laboratory ◽  
Enzymatic Method ◽  
Specific Determination ◽  
Reaction Proceeds ◽  
Clinical Chemistry Laboratory ◽  
Enzymic Assay ◽  
True Values

Abstract This method for the specific determination of methanol in serum is based on the following two reactions: (formula; see text) Alcohol oxidase is not specific: it converts all lower alcohols to their corresponding aldehydes; however, formaldehyde dehydrogenase is specific and thus the transformation of NAD+ to NADH (which is used to monitor the reaction) proceeds only if methanol is originally present in the sample. The method was automated with a Roche COBAS FARA centrifugal analyzer. The calibration curve is linear between 0.6 and 12 mmol/L. The detection limit is about 0.6 mmol/L. The CV is 4.6% for a concentration of 3 mmol/L. When 55 serum specimens known to be free of methanol were supplemented with known amounts of methanol and analyzed by the enzymatic method, the results correlated well (r = 0.987) with the true values, the regression equation being: y = 1.016x + 0.661, where x represents the true values. Results are not affected by other alcohols that may be present in serum, by methanol metabolites, or by some commonly prescribed drugs. The major advantage of this new assay is that it can be used 24 h a day in any clinical chemistry laboratory.

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