Short Prewarming at 41°C to Correct the Interference in Samples with the Presence of Cold Agglutination.

Background: Cold agglutinins (CAs) in blood samples can cause a reversible agglutination of red blood cell (RBC) which result in an incorrect complete blood count (CBC). So, it is important to explore new simple and feasible treatment conditions for clinical work.

Methods: The CAs group included 32 samples with CAs. The parameters of CBC at room temperature or after prewarming at 37°C or 41°C for different time periods were compared. The consistency and correlation of those parameters were analyzed. The morphology of erythrocytes in the CAs group was observed manually. The control group included 45 samples without CAs and prewarmed at 37°C or 41°C for different time periods. The differences were also analyzed.

Results: CAs have a significant effect on CBC. After prewarming at 37°C or 41°C the interferences are all corrected. Consider prewarming at 37°C for 120 minutes as the standard procedure. The consistency and correlation analysis showed there was no statistical difference between the results of each subgroup and standard group, except the MCHC of group 41°C 10 minutes. The correlation of parameters between all subgroups and the standard group is satisfied. Microscopic examination showed no RBC aggregation or fragmentation after prewarming at 41°C or 37°C. According to the maximum bias requirements for expert performance in Validation, Verification, and Quality Assurance of Automated Hematology Analyzers, 2nd Edition (CLSI H26-A2), the differences in overall results in control group are negligible.

Conclusions: The 41°C 2 minutes prewarming method is a rapid and effective way for treating samples with CAs. It is an efficient way to obtain more reliable CBC results, without specific instruments.