Analytical and Clinical Evaluation of the New Tosoh G8 Analyser for HbA1c Measurement

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Background:

Data from the Diabetes Control and Complications Trial (DCCT) have demonstrated that intensive therapy delays the onset and progression of diabetic complications in patients with type 1 diabetes. The UK Prospective Diabetes Study (UKPDS) also emphasized that strict blood glucose control reduces the risk of complication in the type 2 diabetic patients. HbA1c is now widely used for glycemic control and there exists several analytical techniques which are precise and easy to use, allowing automation of the assays and real-time analysis in diabetes clinics.

Aim of the study:

The aim of the study was to evaluate the analytical and clinical performances of the new TOSOH G8 analyser for measuring HbA1c in blood samples

by HPLC.The G8System was compared to Hb HA8160 Arkray System.

5. Analysis of samples with acetylated Hb

6. Analysis of samples with hyperglycemia Hb

7. Identification of Hb variants

HbA1c was determined without inteference in samples containing Hb variants (HbS, HbC, HbD, HbE and HbF).

1. Precision

Within-assay and between-assay CVs were determined on 3 patients samples.

2. Linearity

Assaying serial dilutions of samples with high HbA1c concentrations demonstrated excellent linearity.

3. Correlation with HA 8160 Arkray System

Results of the G8 System were in close correlation (n = 220, R² = 0.99) with those of the HA 8160 Arkray System.

4. Analysis of samples with carbamylated Hb

There was no interference from carbamylated Hb which is completely separated from the HbA1c fraction. In renal failure patients with elevated carbamylated Hb, the correlation with the HA 8160 System, also known to determine HbA1c without interference from carbamylated Hb, was excellent.

Analytical and Clinical Evaluation of the New TOSOH G8

analyser for HbA1c measurement

Teixeira J., Aldenhoff M.C. and Chapelle J.P.

Department of Clinical Chemistry, University Hospital of Liège, Sart Tilman, Liège 4000, Belgium

Department of Clinical Chemistry, University Hospital of Liège, Sart Tilman, Liège 4000, Belgium.

Methods and results

8. Practical Aspects

The G8 System is easy to use. The touch-sensitive screen is very practical. The function STAT allows to give priority to urgent samples. Other advantages: obtaining results in a very short time (1.6 min/sample) , weak consumption in reagent, detection of main Hb variants.

9. Conclusion

In spite of markedly reduced measurement time as compared to the G7 System, the new TOSOH G8 has excellent analytical performances in terms of precision, linearity and absence of interference from carbamylated Hb and abnormal hemoglobins.

HbS HbC HbE HbF HbD G8 HA 8160 %HbA1c %HbA1c Patient HG.1 18,31 18,30 Patient HG.2 10,39 10,60 Patient HG.3 12,98 13,10 Patient HG.4 12,15 12,50 Patient HG.5 13,50 13,40 Patient HG.6 11,08 11,30 G8 HA 8160 %HbA1c %HbA1c Patient A.1 10,17 10,00 Patient A.2 10,20 10,00 Patient A.3 10,54 10,30 Patient A.4 7,86 7,40 Patient A.5 10,60 10,10 Patient A.6 8,28 8,50 G8 HA 8160 Plasma urea %HbA1c %HbA1c g/L Patient C.1 6,65 6,60 1,48 Patient C.2 7,70 7,50 2,12 Patient C.3 5,36 5,20 1,50 Patient C.4 10,14 10,40 1,02

Patient 1 Patient 2 Patient 3 Patient 1 Patient 2 Patient 3 Mean ( %HbA1c ) 4,63 7,71 14,33 Mean ( %HbA1c ) 4,68 7,72 13,96 SD ( %HbA1c ) 0,03 0,03 0,03 SD ( %HbA1c ) 0,08 0,08 0,25

%CV 0,65 0,36 0,19 %CV 1,67 1,01 1,82

Within-assay ( 20 replicates ) Between-assay ( 15 days )

Patient 4 %HbA1c Dilution Total Area %HbA1c % of inicial value

5,74 1/25 7255,90 1/50 3946,35 5,88 102,44 1/100 2028,64 5,82 101,39 1/200 1039,43 5,77 100,52 1/500 405,85 1/1000 208,69 Patient 5 14,73 1/25 8060,00 1/50 4404,00 1/100 2250,20 14,83 100,68 1/200 1166,18 14,67 99,59 1/500 480,66 1/1000 246,29