Capillary Blood Collection Methods: An assessment of different collections technologies compared to traditional venous sampling.

Background There are an increasing number of capillary blood collection devices on the market but little information about their relative performance. Objective To assess the relative performance of four methods to collect capillary blood for donor experience, sample quality and clinical performance and compare to venous sampling. Methods Capillary samples were collected using each of the four methods (traditional lancet, Tasso+, RedDropTM and Touch Activated Phlebotomy II (TAP II) from volunteers (n=26) along with comparative venous samples. Donor experience, pre-analytical performance and clinical acceptability were assessed. Results For donor experience and sample quality, the Tasso+ performed the best device closely followed by RedDrop. No significant differences were seen between methods in the collected blood weight (p>0.05) but the RedDrop showed significantly higher haemolysis (p<0.01). Regarding clinical performance, all analytes except potassium showed mean differences less than their corresponding reference change value for all methods. Most analytes showed high agreement to venous sampling with concordance correlation coefficients (CCC) ≥ 0.7. Excluding potassium, the lowest CCC was for total protein when collected by the lancet method (CCC 0.35. 95% confidence interval -0.11-0.69). Moderate CCCs (0.5-0.7) were seen for calcium, sodium, phosphate and total protein but only when collected by some methods. Conclusion All devices tested are suitable for clinical use for most of analytes investigated. These devices can present a promising patient-centric approach to blood collection but further largescale studies are needed to look at the potential impact of the use of capillary blood on clinical results on an analyte specific basis.