Hb Knossos (HBB: c.82G > T), β-globin CD 5 (-CT) (HBB: c.17_18delCT) and δ-globin CD 59 (-a) (HBD: c.179delA) mutations in a Syrian patient with β-thalassemia intermedia

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.

Capillary electrophoresis based on nucleic acid analysis for diagnosing inherited diseases

Most hereditary diseases are incurable, but their deterioration could be delayed or stopped if diagnosed timely. It is thus imperative to explore the state-of-the-art and high-efficient diagnostic techniques for precise analysis of the symptoms or early diagnosis of pre-symptoms. Diagnostics based on clinical presentations, hard to distinguish different phenotypes of the same genotype, or different genotypes displaying similar phenotypes, are incapable of pre-warning the disease status. Molecular diagnosis is ahead of harmful phenotype exhibition. However, conventional gold-standard molecular classifications, such as karyotype analysis, Southern blotting (SB) and sequencing, suffer drawbacks like low automation, low throughput, prolonged duration, being labor intensive and high cost. Also, deficiency in flexibility and diversity is observed to accommodate the development of precise and individualized diagnostics. The aforementioned pitfalls make them unadaptable to the increasing clinical demand for detecting and interpreting numerous samples in a rapid, accurate, high-throughput and cost-effective manner. Nevertheless, capillary electrophoresis based on genetic information analysis, with advantages of automation, high speed, high throughput, high efficiency, high resolution, digitization, versatility, miniature and cost-efficiency, coupled with flexible-designed PCR strategies in sample preparation (PCR-CE), exhibit an excellent power in deciphering cryptic molecular information of superficial symptoms of genetic diseases, and can analyze in parallel a large number of samples in a single PCR-CE, thereby providing an alternative, accurate, customized and timely diagnostic tool for routine screening of clinical samples on a large scale. Thus, the present study focuses on CE-based nucleic acid analysis used for inherited disease diagnosis. Also, the limitations and challenges of this PCR-CE for diagnosing hereditary diseases are discussed.