Activity 8

• Drops of blood for testing can be obtained by puncturing or making an incision in the capillary bed in the dermal layer of the skin with a lancet, other sharp devices, or laser. With the advent of laboratory instrumentation capable of testing small sample volumes, specimens for many laboratory tests can now be collected in this manner.
• The skin should be warm, pink, and free from scars, cuts, rashes, or bruises. The sites to consider for dermal puncture are the third and fourth fingers in children and adults and the heel in infants.
• capillary puncture site selection recommended areas

  heel; medial and lateral plantar surfaces

  central fleshy area of third and fourth fingers

  across fingerprint lines
• capillary puncture site selection areas not recommended

  back of heel, bottom of foot, arch of foot

  callused finger (usually index finger), thumb, or pinkie

  along fingerprint lines

  areas with visible damage or edema

  sites previously used for dermal puncture
• For a correct dermal puncture, (a) cut across the fingerprint; (b) do not cut in the same direction as the fingerprint.