Effect of blood collection tube type on thyroid status

Abstract

The choice of Blood collection tubes has a direct impact on the quality of biochemical test results. Some components of the tubes may interfere with immunoassays. We have chosen to study the influence of the nature of five tubes without anticoagulants (a glass tube, a plastic tube, and three vacutainer tubes: Vacutest^® , BD^® and SD^®) on the results of two parameters of thyroid status: free thyroxin and thyroid stimulating hormone measured by electrochemiluminescence on the Cobas e 411 analyzer (Roche Diagnostics). Our study has thirty adult volunteers. The glass tube is inert that is why we took it for reference. The mean percentage deviation was calculated for each hormone in each of the five tubes and compared to the total change limit that takes into account analytical and intra-individual imprecisions. The Bland-Altman plot showed no significant difference for the determination of free L-thyroxine and thyroid stimulating hormone on the glass tube versus the other tubes. Variation in serum. thyroid stimulating hormone as well as in free thyroxin concentrations , between the different tubes had no clinical significance since the mean percentage deviation was always lower than the total change limit. Thus, glass, plastic, Vacutest^®, BD^® and SD^® blood collection tubes without anticoagulants; can be used for the determination of free thyroxin and thyroid stimulating hormone.