Carryover impacts on biochemical analytes preceding with whole blood HbA1C samples on automated chemistry

Abstract

Background: Automated clinical chemistry analyzers, employing robotic pipetting and cuvette washing systems, are the stan cxdard means for processing patient specimens. The pipetting and washing systems are designed to continuously sample patient specimens and clean sample probes and reaction cuvettes or vessels. An obvious concern is the potential for carryover of analyte from one patient specimen into another or more following patient specimens. Moreover, the sedimentation time of the blood before the sampling process may vary from lab to the other, depending on the device and protocol used, affecting the analysis outcomes.

Objectives: This study aimed to examine the continued effects of residue carried by the sample probe used in whole blood HbA1c analysis on other biochemical analyses performed by the automated system and determine the relationship of the HbA1c level with the sedimentation time of red blood cells.

Methods: This cross-sectional analysis was performed on an archive of blood samples of 100 type-2 diabetic (T2DM) patients collected from May to June 2023. Blood sedimentation time varied from 0 to 7, 15 to 30 min. The samples were analyzed for cumulative sugar levels (HbA1c) with the enzymatic assay, and sample carryover was assessed using Alinity C modules (Abbott Diagnostics, USA). The levels of HbA1c at the initial time point (0 min; T0) were compared with the levels at three different time points (7 min; T1, 15 min; T2, and 30 min; T3).

Results: The carried-over potassium, AST, ALT, ALP, and CPK values are 0.002 ± 0.068 mmol/L, - 0.040 ± 1.008 U/ L, - 0.100 ± 1.454 U/L, -0.080 ± 1.550 U/L, and 0.060 ± 1.308 U/L, respectively. There is no significant difference in the HbA1c level in all comparison groups (T0-T1: 7.0 ± 1.3, T0-T2: 7.0 ± 1.3, T0-T3: 7.1 ± 1.3). The HbA1c values at the initial time point positively correlated with those found in three different 3 time periods (0 - 7 min (T1); r = 0.9990; P < 0.001, 0 - 15 min (T2); r = 0.9985; P < 0.001, and 0 - 30 min (T3); r = 0.9986; P < 0.001), respectively.

Conclusion: Our study demonstrates that carryover residues from 0, 7, 15, and 30 minutes do not interfere with the HbA1c level and other clinical chemistry test results performed by the automated analyzer. Additionally, HbA1c values were not affected by the sedimentation time of red blood cells (up to 30 min).