Can the Afinion HbA1c Point-of-Care instrument be an alternative method for the Tosoh G8 in the case of Hb-Tacoma?

ABSTRACT

Background: Hb-variant interference when reporting HbA1c has been an ongoing challenge since HbA1c was introduced to monitor patients with diabetes mellitus. Most Hb-variants show an abnormal chromatogram when cation-exchange HPLC is used for the determination of HbA1c. Unfortunately, the Tosoh G8 generates what appears to be normal chromatogram in the presence of Hb-Tacoma, yielding a falsely high HbA1c value. The primary aim of the study was to investigate if the Afinion HbA1c point-of-care (POC) instrument could be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.

Methods: Whole blood samples were collected in K₂EDTA tubes from individuals homozygous for HbA (n = 40) and heterozygous for Hb-Tacoma (n = 20). Samples were then immediately analyzed with the Afinion POC instrument. After analysis, aliquots of each sample were frozen at −80 °C. The frozen samples were shipped on dry ice to the European Reference Laboratory for Glycohemoglobin (ERL) and analyzed with three International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and National Glycohemoglobin Standardization Program (NGSP) Secondary Reference Measurement Procedures (SRMPs). The Premier Hb9210 was used as the reference method.

Results: When compared to the reference method, samples with Hb-Tacoma yielded mean relative differences of 31.8% on the Tosoh G8, 21.5% on the Roche Tina-quant Gen. 2 and 16.8% on the Afinion. Conclusions: The Afinion cannot be used as an alternative method for the Tosoh G8 when testing for HbA1c in the presence of Hb-Tacoma.

KEYWORDS:

• Diabetes mellitus
• HbA1c
• Hb-Tacoma
• HPLC
• immunoassay
• point-of-care

This article is related to:

Hemoglobin amino acids by the numbers

Acknowledgements

We would like to thank Kari Åkerman and Petra Anttila from the Department of Clinical Chemistry, the Hospital District of South Ostrobothnia, Finland for collecting the samples and for the analysis of the samples on the Afinion instrument and Alere Technologies, Vantaa, Finland, for the supply of the cartridges for the Afinion instrument.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.