When a phlebotomist performs a heel stick for the purposes of obtaining a PKU test, it is important to:

Choice A reason:
Gastrin is a hormone that stimulates the secretion of gastric acid by the stomach. While it is a critical component in the digestive process, gastrin is not typically sensitive to light, and therefore, does not require protection from light during handling and transportation.

Choice B reason:
Ammonia testing involves measuring the amount of ammonia in the blood, which can indicate liver function and is used in the diagnosis of hepatic encephalopathy. Ammonia levels are not generally affected by light; thus, special precautions to protect from light are not necessary.

Choice C reason:
Pyruvate is a key intermediate in several metabolic pathways throughout the cell. Pyruvate itself is not considered photosensitive, and standard precautions for handling and transportation are sufficient to maintain its integrity.

Choice D reason:
Bilirubin is a breakdown product of red blood cells and is measured to evaluate liver function and to assess jaundice. Bilirubin is known to be photosensitive; exposure to light can cause it to break down, which can affect the accuracy of test results. Therefore, specimens for bilirubin testing must be protected from light during handling and transportation to ensure valid results.

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.