CT Scans are usually done initially ev. 3 mos for the first year, then ev. 6 mos., then once a year. The blood tests you need done are a Complete Chemistry, including ALT, AST, Alk. Phosphase, a Liver/Kidney function test and Transaminase. Tarceva affects the liver and kidneys. I got this information direction from the pharmacists who work for the drug manufacturing company. My own oncologist completely ignores ordering the right tests and I have to remind her. Tarceva does not affect the CBC count (most doctors do not know this) although your doctor will want a CBC all the time to see if you have infection or anemia. The time frame is up to your doctor, but I would say you need to have the chemistry and liver function tests done at least ev. 6 mos. if not more often.
Good luck.