When calculating total blood volume for a full-term, 2-day-old infant, which of the following information should a phlebotomist consider?

Choice A reason:
The light green tube typically contains lithium heparin and is used for plasma determinations in chemistry. It is not suitable for coagulation studies, such as PT, because heparin is an anticoagulant that would interfere with the test results.

Choice B reason:
The lavender tube contains EDTA, which is an anticoagulant that binds calcium. While it is commonly used for complete blood counts (CBC) and other hematology tests, it is not appropriate for coagulation studies because the binding of calcium would affect the clotting process required for a PT test.

Choice C reason:
The royal blue tube can come with different additives or be additive-free, depending on the color of the closure. It is primarily used for trace element testing, toxicology, and nutrient determinations. The additives in a royal blue tube could potentially contaminate the sample and interfere with the PT test.

Choice D reason:
The light blue tube contains sodium citrate, which is the appropriate anticoagulant for coagulation studies like PT. Sodium citrate works by binding calcium in the blood, preventing clotting. The PT test measures the time it takes for a clot to form after re-calcification, making the light blue tube the correct choice for this test.

Choice A reason:
The flavor of the glucose solution is not a relevant factor to document during a glucose tolerance test. The flavor does not affect the test outcome and is not a required piece of information for the test's validity or interpretation.

Choice B reason:
Documenting the time the glucose load was completed is crucial. The glucose tolerance test is time-sensitive, and blood samples are taken at specific intervals after the glucose solution is ingested. Accurate timing ensures that the results are valid and that any changes in blood glucose levels are correctly attributed to the patient's metabolic response to the glucose load.

Choice C reason:
While the amount of water ingested during the procedure may be noted for patient comfort, it is not typically a required piece of documentation. The focus of the glucose tolerance test is on the patient's response to the glucose solution, not on the volume of water consumed.

Choice D reason:
The volume of blood obtained during the procedure is generally standardized based on the test requirements and does not need to be documented each time. The phlebotomist must ensure that enough blood is collected for the analysis, but the exact volume is determined by the collection tubes used, which are designed to draw a specific volume.