Is treadmill test good enough to rule out possible coronary artery and heart disease?

No. Many times in medicine a single test cannot be counted on to rule out disease completely. Even though stress testing is a very good test to evaluate the blood flow to the heart, it is only one piece of the diagnostic puzzle and sometimes a cardiac catheterization is needed to better decide if there is a problem.
Probably. But not with absoulute 100% certainty. Still, it is a highly useful test.

Related Questions

Can an EKG treadmill test with normal results rule out heart disease? Or do I need other tests to test for CAD & heart structure problems or blockage?

Probably. If you are healthy 36 y/o woman with no symptoms and no risk factors, then probably normal exercise stress test is all you need. If you have risk factors or symptoms, then you could consider coronary cta, nuclear stress test or even cardiac cath. Read more...
Usually. Exercise ekg will give a diagnosis of CAD if abnormal. Other heart diseases need an echo to rule out. If you have no symptoms you don't need multiple tests. Read more...