Dear Dr.,

I am in Brazil and need to take a resistance test. The lab informed my physician that I need to have over 1,000 copies detectable, so this means I need to stop medication and let the virus load grow from 150 copies to 1,000 or more. Is this true? In therory, isn't one copy enough for the test? If I don't need that high load for the test, can you recommend a lab in the USA that performs this test? The one they have here costs about 600 dollars, so if the test in the USA is more sensitive and costs about the same I might as well just have my blood sample sent to the USA. Thank you very much.

Most labs in the US can't get reliable resistance tests from samples with <500-1,000 copies/ml. So what the lab is quoting you is correct. There are a few highly specialized labs which are working on techniques to be able to do resistance testing on samples at 50-100 copies. This is not readily available. Given your copy number, it would be unlikely that a result could be generated. I am not sure I would recommend a drug holiday just to get a high enough viral load to do the test.

MH