71. A phlebotomist needs to collect a PT from a patient with a difficult vein. Which of the following is the best tube for the draw?
Answer: D
Light blue is the best tube for collecting a PT from a patient with a difficult vein.
The light blue tube is specifically designed for coagulation studies, including prothrombin time (PT) testing. Its optimal additive and volume are critical for accurate results, especially when dealing with challenging venous access.
A) Light green
The light green tube contains lithium heparin, which is suitable for plasma determinations in chemistry tests but not appropriate for coagulation studies like PT. Hence, it is not the best choice for this scenario.
B) Lavender
The lavender tube contains EDTA, an anticoagulant used primarily for hematology tests. While it is effective for blood counts, it is not suitable for PT testing, making it an incorrect choice for this requirement.
C) Royal blue
The royal blue tube is used for trace metal analysis and may contain either EDTA or no additive. It is not designed for coagulation tests and would yield inaccurate results for PT, thus making it an unsuitable option.
D) Light blue
The light blue tube contains sodium citrate, which is the standard for coagulation tests, including PT. Its correct volume and additive are essential for ensuring accurate test results, particularly in patients with difficult veins.
Conclusion
The light blue tube is the optimal choice for collecting a PT sample due to its formulation that supports coagulation testing. Other options, including light green, lavender, and royal blue tubes, do not meet the necessary criteria for accurate PT testing, making them less suitable for the phlebotomist's needs in this situation.