What is an 'undetectable' HIV viral load?

What is an 'undetectable' HIV viral load?

Charles Farthing (Chief of Medicine, AIDS Healthcare Foundation) gives expert video advice on: Why do I need to take lab tests if I have HIV? and more...

If you have an undetectable viral load, it doesn't necessarily mean you've got zero copies of HIV in your blood, it means you have less than 50 copies of the virus, and sometimes that means a viral load of zero, and sometimes it might mean a viral load of 20 or 30. The viral load test is usually not read out as 20 or 30 because the accuracy of that determination isn't good enough to give an actual number. Some laboratories report viral load undetectable, which means zero. Other laboratories report just less than 50.