A phlebotomist should recognize that the Clinical and Laboratory Standards Institute (CLSI) recommends that a heel stick depth should not penetrate deeper than which of the following depths for an infant patient?

Choice A Reason:
Hemostasis is the process of blood clotting and the cessation of bleeding. While it is a desired outcome following any puncture, squeezing the puncture site would not typically cause hemostasis as a complication. It is the body's natural response to injury to prevent excessive blood loss.

Choice B Reason:
Hemolysis refers to the rupture of red blood cells, which can occur when excessive pressure is applied to a puncture site during a capillary blood collection. This pressure can cause the cells to burst, releasing their contents into the plasma, which can interfere with various laboratory tests and lead to inaccurate results.

Choice C Reason:
Homeostasis is the body's ability to maintain a stable internal environment despite changes in external conditions. It is not a complication but rather a regulatory process. Squeezing a puncture site does not directly relate to homeostasis as a complication.

Choice D Reason:
Hypobilirubinemia is a condition where there is less than the normal amount of bilirubin in the blood. It is not a complication associated with squeezing a puncture site. Bilirubin levels are typically affected by liver function and red blood cell breakdown, not by the mechanical action of squeezing a site.

Choice A Reason:
The recommended heel stick depth of 2.0 mm is based on the need to minimize the risk of injury to the infant. Penetrating deeper than this can increase the likelihood of hitting bone, which in infants can be as close as 2.0 mm under the skin of the plantar surface of the heel. This depth is sufficient to obtain a blood sample without risking injury to deeper tissues or bone.

Choice B Reason:
A depth of 2.5 mm may be too deep for some infants, especially preterm or very small infants, where the calcaneus (heel bone) is closer to the surface. While this depth might still be safe for some infants, it does not provide the same margin of safety as the 2.0 mm recommendation and could potentially lead to bone puncture or other injuries.

Choice C Reason:
A depth of 3.0 mm significantly increases the risk of bone puncture, especially in infants with less subcutaneous fat or in those who are preterm. This depth could easily breach the protective layer of skin and subcutaneous tissue, leading to a higher risk of osteomyelitis, an infection of the bone, which can be a serious complication in infants.

Choice D Reason:
A depth of 3.5 mm is considered too deep for a heel stick procedure and is likely to cause injury to the infant. This depth would almost certainly penetrate the bone in most infants, leading to severe pain, potential for infection, and other complications. It is well beyond the safe range recommended by CLSI and should be avoided.