Which test is commonly done with a green top tube?

Which test is commonly done with a green top tube?

• A. Complete blood count
• B. Ammonia levels and electrolytes
• C. Glucose tolerance tests
• D. Thyroid function tests

Answer: (B)

The green top tube is primarily used for tests that require heparin as an anticoagulant. This tube is especially useful in the analysis of ammonia levels and electrolytes because heparin allows for the preservation of plasma without clotting, making it ideal for these specific tests. Ammonia levels, in particular, are sensitive to the metabolic processes of blood cells, and the use of a heparinized plasma specimen helps maintain the integrity of the sample by preventing cellular metabolism that could alter the results. Additionally, electrolytes are commonly measured in heparinized plasma, which retains the ionic composition without interference from clotting factors. The other tests listed are typically not conducted using a green top tube, as they require either different types of collection tubes or specific anticoagulants that serve other purposes.

The green top tube is primarily used for tests that require heparin as an anticoagulant. This tube is especially useful in the analysis of ammonia levels and electrolytes because heparin allows for the preservation of plasma without clotting, making it ideal for these specific tests. Ammonia levels, in particular, are sensitive to the metabolic processes of blood cells, and the use of a heparinized plasma specimen helps maintain the integrity of the sample by preventing cellular metabolism that could alter the results. Additionally, electrolytes are commonly measured in heparinized plasma, which retains the ionic composition without interference from clotting factors.

The other tests listed are typically not conducted using a green top tube, as they require either different types of collection tubes or specific anticoagulants that serve other purposes.