A high-throughput test for diabetes care: An evaluation of the next generation Roche Cobas c 513 hemoglobin A1C assay

Performance Evaluation of the DxC 700 AU Chemistry Analyzer in Hemoglobin A1c Measurement

Background

Accurate measurement of glycated hemoglobin (HbA1c) is crucial for a diabetes diagnosis and subsequent patient management. The detection method and presence of variant Hb can interfere with HbA1c measurements. We evaluated the HbA1c-measuring performance of the DxC 700 AU (Beckman Coulter, Brea, CA, USA) immunoassay-based device in comparison with another immunoassay device and the reference method.

Methods

A total of 120 normal and 14 variant Hb samples were analyzed using the Cobas c 513 (Roche Diagnostics, Mannheim, Germany) and DxC 700 AU analyzers. Variant Hb samples were also analyzed using the reference method, along with 20 normal samples. The accuracy, precision, linearity, and carryover were determined.

Results

DxC 700 AU results strongly correlated with those of Cobas c 513 and exhibited accuracy in comparison with the reference method. The within-run, between-run, between-day, and total imprecision (%CV) values for the low- and high-concentration control materials were below 2%. The results of DxC 700 AU were linear over a wide HbA1c range (3.39%-18.30%). Although DxC 700 AU performed well in the presence of variant Hb, the HbA1c concentration was underestimated in the presence of fetal Hb. The possibility of interference from a high HbH proportion could not be ruled out.

Conclusions

The overall analytical performance of DxC 700 AU was acceptable. The device is accurate, precise, and linear over a wide HbA1c concentration range. Although DxC 700 AU results highly correlated with those of Cobas c 513, caution should be exercised in cases of high HbF and HbH concentrations.

A step towards optimal efficiency of HbA1c measurement as a first-line laboratory test: the TOP-HOLE (Towards OPtimal glycoHemOgLobin tEsting) project

OBJECTIVES

The TOP-HOLE (Towards OPtimal glycoHemOgLobin tEsting) project aimed to validate the HbA_1c enzymatic method on the Abbott Alinity c platform and to implement the HbA_1c testing process on the total laboratory automation (TLA) system of our institution.

METHODS

Three different measuring systems were employed: Architect c4000 stand-alone (s-a), Alinity c s-a, and Alinity c TLA. Eight frozen whole blood samples, IFCC value-assigned, were used for checking trueness. A comparison study testing transferability of HbA_1c results from Architect to Alinity was also performed. The alignment of Alinity TLA vs. s-a was verified and the measurement uncertainty (MU) estimated according to ISO 20914:2019. Turnaround time (TAT) and full time equivalent (FTE) were used as efficiency indicators.

RESULTS

For HbA_1c concentrations covering cut-offs adopted in clinical setting, the bias for both Architect and Alinity s-a was negligible. When compared with Architect, Alinity showed a mean positive bias of 0.54 mmol/mol, corresponding to a mean difference of 0.87%. A perfect alignment of Alinity TLA to the Alinity s-a was shown, and a MU of 1.58% was obtained, widely fulfilling the desirable 3.0% goal. After the full automation of HbA_1c testing, 90% of results were released with a maximum TAT of 1 h, 0.30 FTE resource was also saved.

CONCLUSIONS

The traceability of Alinity HbA_1c enzymatic assay to the IFCC reference system was correctly implemented. We successfully completed the integration of the HbA_1c testing on our TLA system, without worsening the optimal analytical performance. The shift of HbA_1c testing from s-a mode to TLA significantly decreased TAT.

Faster HbA1c Turnaround Times Using a Dedicated Analyzer Based on Turbidimetric Inhibition Immunoassay Technology

INTRODUCTION

The Roche Cobas c513 (c513) is a dedicated stand-alone high throughput HbA1c analyzer. We evaluated the performance and the difference in turnaround times (TAT) of the c513 against our Cobas 8000 c502 (c502).

METHODS

We assessed the linearity and precision of the c513, and its agreement (Deming regression and Bland-Altman analysis) with the c502 assay. We compared TAT for these analyzers for a single run of 50 samples and for all samples run over 2 comparable time periods.

RESULTS

The c513 assay was linear from 4.4-18.3% HbA1c. Interassay precision (CV%) was 1.2 and 0.8 at HbA1c levels of 5.7 and 10.5%, respectively. The c513 assay showed excellent concordance with the c502 assay (r = 0.997) with no significant difference between methods by Bland-Altman analysis (mean difference = 0.021% HbA1c, P = 0.1422). The c513 took 17 min to analyze 50 samples, compared to 40 min on the c502. Over comparable 2-month periods, 90% of samples requiring HbA1c tests only were completed under 25 min (c513) vs 30-35 min (c502). For tubes sharing complete blood count (CBC) testing with HbA1c, the 90th percentile TAT was 35-40 min (c513) compared to 45-50 min (c502).

CONCLUSION

The c513 assay performs well with excellent correlation to the c502 assay. The improved TAT of the c513 is suitable when there are demands for rapid HbA1c results and it may forestall requests for point-of-care testing. It is also attractive to sites with heavy workloads with a claimed throughput of 400 tests / h.