Undefilled blood tube containing EDTA: Is it an inappropriate sample for HbA1c assay?
Author(s): Guven B, Benice I, Can M
Publication: Biochem Med (Zagreb), 2023, Vol. 33, Page 010901
PubMed ID: 36817854 PubMed Review Paper? No
Purpose of Paper
This paper compared levels of glycated hemoglobin (HbA1c) in K3EDTA collection tubes that were underfilled or filled appropriately with blood collected from patients with an unspecified diagnosis.
Conclusion of Paper
K3EDTA blood collection tubes that were filled to <25% of the total allowable volume had a significantly higher percentage of HbA1c than matched tubes that were filled appropriately; HbA1c levels did not differ among tubes that were filled to 25-50% or >50% of the total allowable volume relative to tubes that were filled appropriately. In specimens with HbA1c levels below the clinical cut-off of 6.5%, a mean bias of 1.1% and 1.3% was observed in tubes that were filled to <25% and 25-50%, respectively, but no bias was observed in specimens with a HbA1c level ≥ 6.5%. The authors concluded that K3EDTA tubes should be filled >50% for analysis of HbA1c.
Studies
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Study Purpose
This study compared levels of HbA1c in K3EDTA blood collection tubes that were underfilled and appropriately filled. Blood was collected from 109 patients (diagnosis not specified) into two K3EDTA tubes, one that was filled to the total allowable volume and one that was underfilled. Underfilled tubes were filled to <25% (44 specimens), 25-50% (36 specimens), or >50% (29 specimens) of the total allowable volume. HbA1c levels were quantified at the same time in matched specimens using the Tina-quant HbA1c assay on a Cobas 6000 analyzer.
Summary of Findings:
K3EDTA blood collection tubes that were filled to <25% of the total allowable volume had a significantly higher HbA1c percentage than matched blood collection tubes that were appropriately filled (P=0.03), but no difference in HbA1c levels were observed between tubes that were filled to 25-50% or >50% relative to those that were filled appropriately. HbA1c levels were below the clinical cut-off of 6.5% in 56 (51%) of the appropriately filled tubes and above the cut-off in the remaining 53 (49%) of specimens. For specimens with HbA1c levels <6.5%, the mean bias was 1.1% and 1.3% in tubes that were filled to <25% and 25-50%, respectively, compared to matched specimens in appropriately filled tubes. Interestingly, for specimens with HbA1c levels ≥ 6.5%, the mean bias was 0% in tubes that were filled <25% or 25-50% compared to matched specimens collected in appropriately filled tubes. The authors conclude that K3EDTA tubes should be filled >50% for analysis of HbA1c.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Aliquots and Components Aliquot size/volume Tube filled <25%
Tube filled 25-50%
Tube filled >50%
Tube appropriately filled