False Positives

I understand women could easily have false positives with exercise test. Is it possible to have false negatives with ischemia present.
How much of blockage (% block) should be present, before ischemia becomes noticeable, which I guess would be mild ischemia.  

Thanks.

[CCF CARDIO MD JMF]

Dear Sumi,

No test that we have is perfect.  All tests may provide false negatives and false positives.  In general, an exercise test will predict with about 90% accuracy if positive and an 80% accuracy if negative.  

Much depends on the likelihood of CAD your physician thinks you had going into a test.

I hope this has been useful. I wish you the best of luck. Feel free to write back.

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