Screening of vitamin B12 immune complexes in patients with persistent high levels of serum cobalamine

Abstract

Despite manufacturers' claim that systematical assessment of serum indices does not impact on testing efficiency, there is widespread perception that this practice may increase the turnaround time (TAT). A multicenter investigation was planned to verify TAT and performance of serum indices on five different clinical chemistry analyzers.Twenty study samples prepared from pooled sera of outpatients, emergency department, intensive care unit and dialyzed patients were divided in aliquots and shipped to 5 different laboratories. According to local instrumentation (Beckman Coulter AU5800, Roche Cobas 6000, Siemens Dimension Vista 1500, Abbott Architect c 16000 and Ortho Vitros 5.1/FS) and reagents, 13 clinical chemistry parameters were assayed on all study samples, with or without contextual assessment of serum indices.The TAT with assessment of serum indices modestly or even negligibly increased, and varied from − 0.2 to + 5.0% (i.e., from − 3 to + 85 s). When using the lowest thresholds for sample acceptability, the agreement of hemolysis index (HI) among different instruments was comprised between 0.62 and 1.00 (all p < 0.01), but was higher than 0.80 in only 4/10 cases. The agreement of icteric and lipaemic indices could not be estimated due to the low number of samples exceeding acceptability criteria.The results of this study confirm that systematical measurement of serum indices does not impair instrument efficiency. The comparison of HI also suggests that major harmonization may be advisable for this measure among different manufacturers and instrumentations.