After collecting several evacuated tubes from a patient, the phlebotomist receives a pager message to go to the intensive care unit (ICU) immediately and draw several stats. Because of this page, he or she forgets to properly invert the tubes just collected. Which of the following tests is most likely to be affected by this action?

Question

Quizplus · Accepted Answer

Inverting the sodium citrate tube after collection is critical for proper mixing of anticoagulant with the blood sample. A failure to invert may cause platelet contamination, which may in turn affect clotting factors, especially if the sample is not completely filled. The activated partial thromboplastin time is highly sensitive to platelet contamination in the blood sample, and a failure to invert the tube may result in a falsely prolonged result. Glucose is not affected by delayed inversion of tubes, nor is the ionized calcium in a sealed plain red top tube. Also, CO₂ is not a recognized test in laboratory medicine.

After Collecting Several Evacuated Tubes from a Patient, the Phlebotomist