Venipuncture is the method of choice for blood lead testing as it is less subject to contamination from the skin surface than capillary collection.
Lead Determination - Guidelines for Capillary Blood Collection
0-5 years: 0-3 ug/dL*6-17 years: 0-10 ug/dLAdults (>17 years): 0-25 ug/dL
*Ruckart PZ, Jones RL, Courtney JG, et al. Update of the Blood Lead Reference Value - United States, 2021. MMWR 2021;70:1509-1512.