The phlebotomist must be equipped with knowledge of special laboratory tests. Special tests include timed specimens, glucose tolerance testing, therapeutic phlebotomy collections, bleeding time, blood alcohol, toxicology, chain-of-custody specimens, and therapeutic monitoring of drug levels. Some of these tests require additional preparation and some tests require extra skills. Licensed practitioners depend on the phlebotomist to know the special requirements and adhere to them. Following these special procedures will directly impact the quality of patient care. Patients can affect laboratory results by exercising, eating, fasting, lying down, standing up, being stressed, smoking, or drinking alcohol. Table 6-1 is a list of some laboratory tests that can be affected by different patient behaviors. Phlebotomists are also given the opportunity to educate patients about the laboratory and the importance of following the physician's directions.