A phlebotomist should explain the procedure prior to venipuncture to:

Choice A reason:
The laboratory accession number is a unique identifier assigned to a patient's specimen once it is received by the laboratory. While it is an important piece of information, it is not provided by the physician's office to the phlebotomist for specimen collection. Instead, it is generated by the laboratory after the specimen is collected and submitted for analysis.

Choice B reason:
The Physician's NPI (National Provider Identifier) number is a unique identification number for covered health care providers in the United States. While it is used for billing and identification purposes, it is not the information that the physician's office needs to provide to a phlebotomist for the purpose of specimen collection.

Choice C reason:
The laboratory requisition form is the correct document that should be provided by the physician's office. This form contains the patient's demographic information, the tests ordered by the physician, special instructions for specimen collection, and any other pertinent information required for proper specimen handling and testing.

Choice D reason:
The physician's encounter form typically contains details of the patient's visit, including services provided, diagnoses, and billing information. It is not specifically used for laboratory specimen collection and therefore is not the information that should be provided to a phlebotomist for this purpose.

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.