[Wideband acoustic immittance characteristics and machine learning-based diagnostic model for children with large vestibular aqueduct syndrome].

Objective:This study was to investigate the wideband acoustic immittance（WAI） characteristics of children with large vestibular aqueduct syndrome（LVAS） and to construct a diagnostic model for LVAS based on WAI and machine learning（ML） techniques. Methods:We performed a retrospective analysis of the data from 38 children（76 ears） with LVAS and 44 children（88 ears） with normal hearing. The data included conventional audiological examination, temporal bone CT scan and WAI test. We performed statistical analysis and developed multivariate diagnostic models based on different ML techniques. Results:The two groups were balanced in terms of ear, gender, and age（P>0.05）. The wideband absorbance（WBA） of the LVAS group was significantly lower than that of the control group at 1 000-2 519 Hz, while the WBA of the LVAS group was significantly higher than that of the control group at 4 000-6 349 Hz（P<0.05）. WBA at 5 039 Hz under ambient pressure had a certain diagnostic value（AUC=0.767）. The multivariate diagnostic model had a high diagnostic value（AUC>0.8）, among which the KNN model performed the best（AUC=0.961）. Conclusion:The WAI characteristics of children with LVAS are significantly different from those of normal children. The diagnostic model based on WAI and ML techniques has high accuracy and reliability, and provides new ideas and methods for intelligent diagnosis of LVAS.

Comparable analysis of six immunoassays for carcinoembryonic antigen detection.

Objective: This study aimed to assess the current status of carcinoembryonic antigen (CEA) detection. We evaluated the correlation, consistency, and comparability of CEA results among six automated immunoassays, and combined with the results of CEA trueness verification of the Beijing Center for Clinical Laboratories (BCCL) for further analysis. Methods: Abbott Architect i2000, Beckman DxI800, Roche Cobas E601, Diasorin Liaison XL, Maccura IS1200, and Autolumo A2000 were used to detect 40 individual serum CEA samples. Taking the optimal analytical quality specifications calculated from data on biological variation as the evaluation criterion. Passing-Bablok regression and Bland-Altman analysis were performed between each assay and all-assays median values to evaluate the correlation and relative difference. The concordance correlation coefficient (CCC) was used for consistency analysis. Additionally, the trueness verification program used samples at three concentration levels to assess the bias, coefficient of variation (CV), and total error (TE) between the average measured values and the target value. Results: The Spearman's rank correlation coefficient (rs) was ≥0.996 and the CCC ranged between 0.9448 and 0.9990 for each assay vs. all-assays median. Considering the all-assays median value of each sample as a reference, there were proportional and systematic differences according to the Passing-bablok regression analysis. The relative difference of the four assays (Abbott Architect i2000, Autolumo A2000, Diasorin Liaison XL, and Maccura IS1200) met the optimal analytical quality specifications. On the other hand, Beckman DxI800 (13.2 %) and Roche Cobas E601 (-9.0 %) were only able to fulfill the desirable analytical quality specifications. The average pass rates for bias, CV, and TE of the trueness verification program were 80 %, 98 %, and 96 %, respectively. Conclusions: The six automated immunoassays vs. all-assays median have a good correlation in CEA detection. However, there is a lack of comparability of CEA results. Further improvements are needed in harmonization among CEA detections.

Proteomics analysis of serum and urine identifies VCP and CTSA as potential biomarkers associated with multiple myeloma.

AIMS: We analyzed the differentially expressed proteins (DEPs) in serum and urine in order to provide new potential biomarkers for MM. METHODS: Data-Independent Acquisition-based proteomics of serum and urine was performed to identify potential biomarkers for MM patients. Then we performed Western Blotting (WB), ELISA along with their ROC curve analysis to confirm DEPs. RESULTS: A total of 1653 proteins in serum and 4519 proteins in urine were identified using Data-Dependent Acquisition method. VCP was the only protein that showed significant differences in different comparison groups in both serum and urine. Pathway analysis revealed that protein processing in the endoplasmic reticulum was the most relevant pathway associated with MM. Furthermore, the increased expression of HSP90B1, VCP, CTSA, HYOU1, PDIA4, and RAB7A was detected by WB. The results of ELISA indicated that a combination of VCP and CTSA provided a high area under curve (AUC) value of 0.883 (95 % CI, 0.769-0.997, p < 0.001) to diagnose NDMM. The combination of VCP, CTSA, ALB, and HGB exhibited better performance (AUC = 0.981), with 100 % specificity and 86.7 % sensitivity. CONCLUSION: These findings suggest VCP and CTSA exhibit potential as biomarkers for MM, which may be helpful in the molecular mechanisms and pathogenesis upon further investigation.

Commutability evaluation of candidate reference materials and ERM-DA470k/IFCC for immunoglobulin M using two international approaches.

BACKGROUND: This study aimed to assess the commutability of frozen pooled human serum (PHS), high concentration of Immunoglobulin M (IgM) pure diluted materials (HPDM), commercialized pure materials (CPM), and dilutions of ERM-DA470k/IFCC in IgM detection using the CLSI and IFCC approaches, to support standardization or harmonization of IgM measurement. METHODS: Twenty-four serum samples, relevant reference materials (PHS, HPDM, CPM), and different ERM-DA470k/IFCC dilutions were analyzed in triplicate using six routine methods. The commutability of the relevant reference materials was carried out following CLSI EP30-A and IFCC bias analysis. RESULTS: According to the CLSI approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 13, 15, 13, and 8 of 15 assay combinations, respectively. Using the IFCC approach, low, medium, and high concentrations of PHS, HPDM, and CPM were commutable on 10, 11, 9, 15, and 10 of 15 assay combinations, respectively. The ERM-DA470k/IFCC dilutions with D-PBS and RPMI-1640 Medium were commutable on 13 of 15 assay combinations according to CLSI and were commutable on all 15 assay combinations using IFCC approach. CONCLUSIONS: High concentration of PHS were commutable on all six detection systems using the CLSI approach. Low and medium concentration of PHS showed unsatisfied commutability. HPDM, not CPM have good commutability, has the potential to become reference materials. ERM-DA470k/IFCC diluted with different medium showed different commutability.

Accurate method for value assignment of carcinoembryonic antigen reference materials.

BACKGROUND: In this study, we explored the commutability of reference materials (RMs) for carcinoembryonic antigen (CEA), selected the appropriate diluent matrix of the first International Reference Preparation (IRP) 73/601 of the World Health Organization (WHO 73/601) for CEA, and improved the comparability of CEA measurement results among different assay systems. METHODS: Forty serum samples were divided into five aliquots. WHO 73/601 was diluted into nine concentrations using five diluents with different components, and the candidate RMs for CEA at five concentrations (C1-C5) were prepared by the Beijing Clinical Laboratory Center (BCCL). The samples were analyzed via five automated CEA immunoassays. RESULTS: Carcinoembryonic antigen candidate RMs were commutable among all immunoassays based on the CLSI approach and among 7 of 10 assay combinations based on the IFCC approach. WHO 73/601 diluted in phosphate-buffered saline (PBS) was commutable among all assays based on the CLSI approach and among 5 of 10 pairwise comparisons based on the IFCC approach with correction of bias at diluted concentrations, except for the lowest concentration, which had the smallest variation among systems. The median percentage biases among assays were decreased after calibration. CONCLUSION: The BCCL candidate RMs (C2-C5) for CEA were commutable among all immunoassays. WHO 73/601 RMs diluted in a PBS buffer matrix were selected as common calibrators for five immunoassays, which reduced bias, thereby effectively improving the harmonization of CEA detection; therefore, they could be used to assign values to CEA candidate RMs developed by BCCL. Our findings promote the harmonization of CEA detection in immunoassays.

Assessing the comparability of cycle threshold values derived from five external quality assessment rounds for omicron nucleic acid testing.

BACKGROUND: A variety of open-system real-time reverse transcriptase polymerase chain reaction (RT-PCR) assays for several acute respiratory syndrome coronavirus 2 are currently in use. This study aimed to ensure the quality of omicron nucleic acid testing and to assess the comparability of cycle threshold (Ct) values derived from RT-PCR. METHODS: Five external quality assessment (EQA) rounds using the omicron virus-like particles were organized between February 2022 and June 2022. RESULTS: A total of 1401 qualitative EQA reports have been collected. The overall positive percentage agreement was 99.72%, the negative percentage agreement was 99.75%, and the percent agreement was 99.73%. This study observed a significant variance in Ct values derived from different test systems. There was a wide heterogeneity in PCR efficiency among different RT-PCR kits and inter-laboratories. CONCLUSION: There was strong concordance among laboratories performing qualitative omicron nucleic acid testing. Ct values from qualitative RT-PCR tests should not be used for clinical or epidemiological decision-making to avoid the potential for misinterpretation of the results.

A machine learning-based approach for low-density lipoprotein cholesterol calculation using age, and lipid parameters.

BACKGROUND: Low-density lipoprotein cholesterol (LDL-C) is a critical biomarker for cardiovascular disease. However, no consensus exists on the best method for estimating LDL-C in Chinese laboratories. This study aimed to develop a machine learning (ML) method for LDL-C estimation. METHODS: An extensive data set of 111,448 samples were randomized into five equal subsets. ML-based equations were developed using age, sex, and lipid parameters based on five-fold cross-validation. The trained ML equations were externally validated in three different data sets. The performance of the ML equations was compared with the Friedewald, Martin/Hopkins, and Sampson equations. RESULTS: The selected ML equations showed less bias with direct LDL-C than other LDL-C equations in the Chinese population, including those with triglycerides (TG) ≥ 400 mg / dL and LDL-C < 40 mg / dL. The performance of the ML equations was less susceptible to age. External validation showed the generalization of the ML equations. CONCLUSIONS: This study highlights the potential of integrating sex, age, and lipid parameters into the ML equations to obtain a more robust and reliable LDL-C calculation.

Routine blood biomarkers for the detection of multiple myeloma using machine learning.

INTRODUCTION: Primary laboratory tests performed in the diagnosis of multiple myeloma (MM) include bone marrow examination and free light chain assay; however, these may only be ordered after clinical suspicion of disease. In contrast, routine blood test results are readily available. METHODS: Machine learning algorithms (ML) combined with routine blood tests were used to detect MM. Feature selection was performed to achieve improved classification performance. The robustness of the classification models was assessed in an internal and external validation data set. To minimize the divergence, the training and validation data sets were combined and used to assess the performance of the ML algorithms. RESULTS: The AdaBoost-DecisionTable produced the best performance (accuracy =94.75%, sensitivity =87.70%, positive predictive value (PPV) =92.50%, F-measure =90.00%, and areas under the receiver operating characteristic curves (AUC) =97.50%) in the training data set using a 10-fold cross-validation. Performance in the validation data sets was affected by the divergence of the data sets, with accuracy greater than 85% and AUC greater than 90% in the validation data sets. The ML algorithm achieved a high accuracy of 92.61%, high AUC (96.80%), a sensitivity value of 85.20%, a PPV value of 88.50%, and an F-measure of 86.80% in a test set that was randomly selected from the combined data set. CONCLUSIONS: Combining ML and routine serum biomarkers hold a potential benefit in MM diagnosis.

Comparability of thyroid-stimulating hormone immunoassays using fresh frozen human sera and external quality assessment data.

BACKGROUND: This study aimed to assess the comparability among assays using freshly frozen human sera and external quality assessment (EQA) data in China. METHODS: Twenty-nine serum samples and two commercial EQA materials, obtained from the National Center for Clinical Laboratories (NCCL), were analyzed in triplicate using eight routine TSH assays. The commutability of commercial EQA materials (NCCL materials) was evaluated in accordance with the CLSI EP30-A and IFCC bias analysis. Median values obtained for the NCCL EQA materials were used to determine the systematic and commutability-related biases among immunoassays through back-calculation. The comparability of TSH measurements from a panel of clinical samples and NCCL EQA data was determined on the basis of Passing-Bablok regression. Furthermore, human serum pools were used to perform commutable EQA. RESULTS: NCCL EQA materials displayed commutability among three or five of seven assay combinations according CLSI or IFCC approach, respectively. The mean of systematic bias ranged from -13.78% to 9.85% for the eight routine TSH assays. After correcting for systematic bias, averaged commutability-related biases ranged between -42.26% and 12.19%. After correction for systematic and commutability -related biases, the slopes indicating interassay relatedness ranged from 0.801 to 1.299 using individual human sera, from 0.735 to 1.254 using NCCL EQA data, and from 0.729 to 1.115 using pooled human serum EQA(the commutable EQA). CONCLUSIONS: The harmonization of TSH measurement is challenging; hence, systematic and commutability-related biases should be determined and corrected for accurate comparisons among assays when using human individual serum and the commercial EQA materials.

Homogeneity and Stability Evaluation of External Quality Assessment Control Materials for Four Coagulation Tests.

BACKGROUND: This study assessed the homogeneity and stability of control materials used in external quality assessment (EQA) of four coagulation tests, aiming to verify that these materials meet clinical testing requirements and to provide an evidence base for future improvement of laboratory coagulation test quality. METHODS: The homogeneity and stability of control materials were assessed according to the relevant guidance. Homogeneity assessment involved 10 vials of samples obtained from 2 batches (each vial tested twice). The homogeneity of control materials in four coagulation tests was assessed using one-way analysis of variance, with standard deviation of uniformity (Ss) 0.3 σ as an assessment criterion. Stability assessment involved two vials of sam-ples obtained from two batches (each vial tested twice). The stability of control materials was assessed at cold storage, room temperature, temperature of 37°C. Reconstitution stability of control materials placed in cold storage and at room temperature, and long-term stability of reconstituted control materials stored frozen (-20°C and -80°C) were observed. Linear regression analysis was performed to assess long-term stability. RESULTS: The Ss values of EQA control materials for four coagulation tests were PT L1 Ss = 0.084, PT L2 Ss = 0.889, APTT L1 Ss = 0.164, APTT L2 Ss = 0.223, Fbg L1 Ss = 6.256, Fbg L2 Ss = 2.251, TT L1 Ss = 0.552, TT L2 Ss = 0.3111. PT, APTT, Fbg, and TT were associated with the standard deviation of uniformity values of 0.3 σ. Non-reconstituted samples were observed at 37°C for 2 hours and 4 hours, and at room temperature for 1 day. Reconstituted samples were observed when stored at 4°C for 4 hours and 8 hours, at room temperature for 4 hours, and at -20°C and -80°C for 6 months. Instability of reconstituted samples was observed in PT and APTT tests at 4°C for 8 hours and at -20°C for 5 months. CONCLUSIONS: EQA control materials presented with satisfactory homogeneity in four coagulation tests. Non-reconstituted samples presented with satisfactory stability at 37°C for 2 hours and 4 hours and at room temperature for 1 day, while reconstituted samples presented with satisfactory stability when refrigerated at 4°C for 4 hours, when kept at room temperature for 4 hours, and when frozen at -80°C for 6 months.

Establishment of Multiple Myeloma Diagnostic Model Based on Logistic Regression in Clinical Laboratory.

BACKGROUND: Due to the insidious onset of multiple myeloma (MM), missed diagnosis and misdiagnosis have a serious impact on the health of MM patients. Simple, rapid, and valid laboratory screening is critical for MM clinical diagnosis. METHODS: We used routine laboratory tests to establish a simple, inexpensive, and non-invasive diagnostic model for MM based on logistic regression. In the retrospective analysis, a total of 273 newly diagnosed MM inpatients and 288 non-MM participants, from January 2016 to December 2018 in Beijing Chaoyang hospital, Capital Medical University, were divided into training set and validation set. Age, gender, and the related routine laboratory tests for MM, including albumin (ALB), globulin (GLB), lactate dehydrogenase (LDH), creatinine (Cr), calcium (Ca2+), hemoglobin (Hb) and platelet (PLT), were analyzed by multivariate logistic regression to develop a diagnostic model. RESULTS: A diagnostic model was calculated using the formula MM index=-((-18×gender-3×ALB-Hb)/10), based on the logistic regression. The MM index [22 (20 - 25)] of MM patients was significantly lower than that of non-MM [30 (29 - 31)] in the training set (p < 0.001). It showed an excellent diagnostic performance in diagnosing MM through a receiver operating characteristic (ROC) curve, and its corresponding sensitivity, specificity, and area under the curve (AUC) were 95.6%, 96.7%, and 0.982 (0.968, 0.997), respectively. At a diagnostic risk threshold of 28, the model identified MM with a sensitivity of 95.6% and a specificity of 98.1% by using independent validation data. There was a significant positive correlation (r = 0.845, p < 0.001) between the DS grading and the MM index among all the participants. CONCLUSIONS: The established diagnostic model of MM index can successfully identify newly diagnosed MM from healthy controls. The diagnostic model of MM index may also act as a predictor of the severity of MM without therapy.

Establishment of reference intervals for pediatric complete capillary blood counts: A multicenter study in Beijing.

INTRODUCTION: Clinical reference intervals represent the normal range of clinical parameters for distinguishing healthy and sick individuals, and they show some variation among different populations. Many reference intervals are still lacking for the pediatric population in China. Thus, the aim of this study was to establish and validate pediatric reference intervals for capillary blood cell counts. METHODS: A total of 9942 children were enrolled from 10 medical institutions in Beijing, China, for capillary complete blood count (CCBC) values according to the EP28-A3c guideline issued by the Clinical and Laboratory Standards Institute. RESULTS: Pediatric reference intervals for 17 CCBC parameters were established for children aged 6 months to 7 years. The red blood cell count and red blood cell distribution width were generally higher in males than in females, and the mean corpuscular hemoglobin and mean corpuscular volume were higher in females than in males. The red blood cell, hemoglobin, hematocrit, and neutrophil percentages increased while the percentage of lymphocytes decreased with age. The overall trends for each reference interval were relatively similar in different ethnic groups and regions in the world, but with variation in the upper and lower limits, which confirms the existence of racial and geographical differences. Further validation with 508 healthy subjects showed that the verified proportions were within 90.9%-100% of the reference intervals. CONCLUSIONS: This study offers local reference intervals for CCBC values for the pediatric population in Beijing, China, and thus provides basic criteria for the diagnosis, treatment, and health assessment of childhood diseases in China.

Uncertainty evaluation in clinical chemistry, immunoassay, hematology and coagulation analytes using only external quality assessment data.

BACKGROUND: Measurement uncertainty (MU) is a parameter associated with the result of a measurement that characterizes its dispersion. We report results for estimating MU following the application of a top-down procedure using only proficiency test data to establish uncertainty levels for various analytes. METHODS: Data were obtained from 142 laboratories participating in the Beijing Center for Clinical Laboratory (BCCL) proficiency testing/external quality assessment (PT/EQA) schemes. The 24-month study included six selected PT shipments to obtain estimates for 50th percentile (median) and 90th percentile MUs and to compare those estimates to usual analytic goals. The number of laboratory participants varied for each trial. The expanded uncertainty (U) was calculated using a cover factor of k=2 for a confidence interval of 95%. All reproducibility, method and laboratory biases came from the PT/EQA data. RESULTS: The median U (k=2) ranged from 3.2% (plasma sodium, indirect ion selective electrode) to 32.8% (triglycerides, free glycerol blanking) for clinical chemistry analyte means from participants in the same method group. Immunoassay analyte median U results ranged from 11.3% (CA125 tumor marker, Roche) to 33.8% (prostate-specific antigen [PSA], Abbott). The range for median U was 3.5% (red blood cell [RBC], Abx) to 30.3% (fibrinogen [FBG], other) for hematology and coagulation analytes. The MUs for most analytes satisfied quality requirements. CONCLUSIONS: The use of PT/EQA data, when available, provides an effective means for estimating uncertainties associated with quantitative measurements. Thus, medical laboratories can calculate their own MUs. Proficiency testing organizers can provide participants with an additional MU estimate using only EQA data, which may be updated at the end of each survey.

Application of Commutable ERM-DA474/IFCC for Harmonization of C-reactive Protein Measurement Using Five Analytical Assays.

BACKGROUND: ERM-DA474/IFCC has been used as a reference material for C-reactive protein (CRP) since 2012. However, the commutabilities and the capacity for harmonizing CRP results of the material and its dilutions have not yet been reported. In this study, we aimed to evaluate the harmonization of CRP results using commutable ERM-DA474/IFCC. METHODS: Twenty-one serum samples were collected and split into five vials. The samples were then analyzed using five popular assays (Siemens BN II, Beckman Immage 800, Roche, Diasys, and Leadman). ERM-DA474/IFCC and four dilutions of healthy human serum containing low levels of CRP were also analyzed using the five assays described above. Commutability was assessed using the Roche, Diasys, and Leadman assays. Clinical sample results from assays were recalibrated based on ERM-DA474/IFCC and its dilutions. RESULTS: There were significant variations among the five assays for CRP measurement. The slopes ranged from 0.60 to 1.60, and the BN II and Leadman assays showed significant negative and positive systemic biases, respectively. ERM-DA474/IFCC and its dilutions exhibited commutability among the three assays. After recalibration, the slope was reduced to 0.76 - 1.27. CONCLUSIONS: Harmonization was not ideal for CRP measurement. ERM-DA474/IFCC may play a role in improving harmonization for CRP measurement.

Commutability of Reference Materials for α-Fetoprotein in Human Serum.

CONTEXT: - Reliable quantification of α-fetoprotein (AFP) is critical for clinical diagnosis. Accuracy in AFP analysis relies on traceability to reference materials with confirmed commutability. OBJECTIVE: - To assess the commutability of the reference materials for AFP. We screened for appropriate reference materials for the calibration of clinical AFP analysis and for application in an external quality assessment scheme. The feasibility of using water to dilute a reference material from the World Health Organization was also evaluated. DESIGN: - Patient serum samples with various levels of AFP were randomly interspersed among AFP reference materials from the World Health Organization, the Beijing Center for Clinical Laboratories, and Beijing Controls and Standards Biotechnology and quality controls from Bio-Rad. The samples were analyzed on 5 different platforms to assess the comparability of the results and commutability of the reference materials. RESULTS: - Significant variations in AFP measurement were observed among the 5 instrument platforms. The Beijing Center for Clinical Laboratories and Beijing Controls and Standards Biotechnology reference materials were commutable across all the instrument platforms. The World Health Organization AFP 72/225 reference material diluted with distilled water was also commutable at high concentrations. The Bio-Rad quality control materials for AFP were commutable among 4 out of 5 instrument platforms. CONCLUSIONS: - Our results suggested that the Beijing Center for Clinical Laboratories and Beijing Controls and Standards Biotechnology materials were commutable across all 5 instrument platforms, whereas the Bio-Rad quality controls were limited by the concentration of AFP and the instrument platforms used. Caution needs to be taken in using water to dilute the World Health Organization 72/225 reference material because its commutability is limited to high concentrations.

A long way to go for the harmonization of four immunoassays for carcinoembryonic antigen.

BACKGROUND: Carcinoembryonic antigen (CEA) is one of the most widely used tumor markers worldwide. CEA immunoassays often yield different results. The objective of the present study was to investigate the current state of harmonization among CEA tests. METHODS: A total of 94 individual serum samples were divided into 3 subsets and measured in triplicate using 4 assays, Abbott Architect i2000SR, Beckman Access DXI800, Roche Cobas e601, and Siemens Advia Centaur XP. The standards from each manufacturer and the 1st International Reference Preparation (IRP) 73/601 of the World Health Organization were measured as unknowns in parallel with the patient samples using the 4 assays. The results of an external quality assessment (EQA) scheme for CEA were also analyzed. RESULTS: A perfect correlation was not observed between any 2 assays, and the values obtained using the 4 assays were different for the detection of 94 individual patient serum samples. No consistency was detected in the CEA results evaluated by various assays for EQA samples, individual patient samples, the standards from each manufacturer, and the WHO IRP 73/601. CONCLUSIONS: Harmonization of the CEA results obtained using the 4 immunoassays has not yet been achieved.

Modified HPLC-ESI-MS Method for Glycated Hemoglobin Quantification Based on the IFCC Reference Measurement Procedure and Its Application for Quantitative Analyses in Clinical Laboratories of China.

BACKGROUND: The level of glycated hemoglobin (HbA1c ) has been recognized as an important indicator of long-term glycemic control. However, the HbA1c measurement is not currently included as a diagnostic determinant in China. Current study aims to assess a candidate modified International Federation of Clinical Chemistry reference method for the forthcoming standardization of HbA1c measurements in China. METHODS: The HbA1c concentration was measured using a modified high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method. The modified method replaces the propylcyanide column with a C18 reversed-phase column, which has a lower cost and is more commonly used in China, and uses 0.1% (26.5 mmol/l) formic acid instead of trifluoroacetic acid. Moreover, in order to minimize matrix interference and reduce the running time, a solid-phase extraction was employed. The discrepancies between HbA1c measurements using conventional methods and the HPLC-ESI-MS method were clarified in clinical samples from healthy people and diabetic patients. Corresponding samples were distributed to 89 hospitals in Beijing for external quality assessment. RESULTS: The linearity, reliability, and accuracy of the modified HPLC-ESI-MS method with a shortened running time of 6 min were successfully validated. Out of 89 hospitals evaluated, the relative biases of HbA1c concentrations were < 8% for 74 hospitals and < 5% for 60 hospitals. Compared with other conventional methods, HbA1c concentrations determined by HPLC methods were similar to the values obtained from the current HPLC-ESI-MS method. CONCLUSION: The HPLC-ESI-MS method represents an improvement over existing methods and provides a simple, stable, and rapid HbA1c measurement with strong signal intensities and reduced ion suppression.

Point-of-care testing of HbA1C is traceable to IFCC reference method by external calibration.

BACKGROUND: POCT for HbA1C is widely used in China. However, the lack of traceability of POCT leads to poor comparability of patient results. METHODS: The first step was the evaluation of the precision of NycoCard and DCA by using two-level patient specimens. The second step was the calibration of the central laboratory instrument G8 HBA1C Variant with samples whose values had been assigned by an IFCC reference method. The third step was the assignment of values to 50 fresh whole blood patient specimens by this calibrated G8. The fourth step was to use these 50 fresh whole blood patient specimens to calibrate and to revise the POCT instruments. The fifth step was to confirm whether these 50 specimens were required through mathematical calculations. RESULTS: The low and high CVs at levels were 3.61% and 1.85% for NycoCard but 1.71% and 2.85% for DCA. The linear equation of NycoCard to calibrated G8 and that of DCA to calibrated G8 were Y=0.8530X+0.6409 and Y=0.8995X+0.3891, respectively, and the correlation coefficient for every POCT instrument was greater than 0.985. By external calibration of POCT instruments, the mean deviation detected by NycoCard was reduced from -4.0±3.4mmol/mol to 0.5±3.9mmol/mol, and that by DCA went down to 0.2±3.3mmol/mol. The minimum specimen size for the external calibration of POCT instrument was 10. CONCLUSION: POCT measurement traceability can be established by external calibration. Using an external calibration mode improves the comparability of POCT patient results.