I am no expert, but it's my understanding that blood in the capillaries (fingertip) is not exactly the same as blood in the veins. > In addition, the small vo

I am no expert, but it's my understanding that blood in the capillaries (fingertip) is not exactly the same as blood in the veins. > In addition, the small volumes involved and the variability in sample quality based on puncture site and technique make capillary sampling particularly susceptible to errors during the pre-preanalytical phase, which are beyond the control of clinical laboratory personnel https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4622200/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4622200/