CPT (Certified Phlebotomy Technician) Practice Exam

For a GREY tube, what test is typically run, which anticoagulant is used, and to which lab section is it sent?

1. Blood typing, sodium fluoride, blood bank

2. PK, sodium citrate, chemistry

3. Glucose GTT, sodium fluoride, chemistry

4. Toxicology levels, K2EDTA, toxicology

The correct answer is: Toxicology levels, K2EDTA, toxicology

The grey tube is typically used for certain tests related to glucose and may also be utilized for toxicology levels. The anticoagulant commonly associated with the grey tube is sodium fluoride, which acts as both an anticoagulant and a preservative for glucose testing, ensuring that glucose levels remain stable during the testing process. When it comes to tests performed on samples taken from a grey tube, glucose tolerance tests (GTT) are often conducted, as the sodium fluoride helps to prevent glycolysis, which could skew results. The root function of this tube is primarily linked to the chemistry lab section, where laboratory personnel analyze the samples for various biochemical components, including glucose levels. Therefore, while toxicology levels might be a valid consideration, the grey tube is more directly aligned with tests like glucose assessments and is primarily sent to the chemistry department for analysis. The correct association of test, anticoagulant, and lab section reflects the established use of the grey tube in phlebotomy practices.