Green top tubes are used for conducting a Lytes Panel test. A Lytes Panel is a blood test that measures the levels of electrolytes in the body, including sodium, potassium, chloride, and bicarbonate. These electrolytes are essential for maintaining proper fluid balance, nerve function, and muscle contraction. The green top tube contains an anticoagulant called heparin, which prevents blood clotting and allows for accurate measurement of electrolyte levels. Therefore, the correct answer is Lytes Panel.