Ialongo and Bernardini (1) reviewed 36 investigations of pre-analytical factors related to phlebotomy issued between 1996 and 2016 (April). The largest part of studies had a cohort of healthy volunteers or outpatients, the former group with a smaller sample size. Sample size calculations for detecting a specified effect was addressed only in one manuscript. Student’s t-test and Wilcoxon’s test were often used, but many papers assessed neither bias (12) nor agreement (24).

The authors discuss recommendations for improving methodological consistency and reliable results.


  1. Ialongo C, Bernardini S. Preanalytical investigations of phlebotomy: methodological aspects, pitfalls and recommendations. Biochem Med (Zagreb) 2017;27:177-191.