AbstractPoint 1: Portable x-ray fluorescent (pXRF) technology provides significant opportunities for rapid, non-destructive data collection in a range of fields of study. However, there are sources of variation and sample assumptions that may influence the data obtained, particularly in biological samples.Point 2: We used representative species for four taxa (fish, mammals, birds, reptiles) to test the precision of replicate scans, and the impact of sample thickness, sample state, scan location and scan time on data obtained from a pXRF.Point 3: We detected significant differences in concentration data due to sample state, scanning time and scanning location for all taxa. Infinite thickness assumptions were met for fish, reptile and mammal representatives at all body locations when samples were thawed, but not dried. Infinite thickness was not met for feathers. Scan time results found in most cases the 40, 60 and 80 second beam times were equivalent. Concentration data across replicate scans were highly correlated.Point 4: The opportunities for the use of pXRF in biological studies are wide-ranging. These findings highlight the considerations required when scanning biological samples to ensure the required data are suitably collected, while maintaining minimal radiation exposure to live animals.