More HIV/Aids patients in Africa could be treated if funds were switched from expensive laboratory testing to local care in villages, research suggests.
Results from a six-year clinical trial of 3,500 people showed that lab tests of how anti-retroviral drugs work and side-effects do little to prolong life.
Money saved would enable a third more people to be treated, one doctor said.
In the West, laboratory tests are routinely carried out. There is still no cure for HIV/Aids.
But anti-retroviral drugs can stop the disease from developing.
Scientists in Uganda, Zimbabwe and Britain followed almost 3,500 patients over six years for the study, known as Dart.
Dr Peter Mugyenyi said more than six million people in Africa required care, but only 2.2 million were currently getting it.
The laboratory tests are very hard to carry out in most of Africa, the research suggests.
The difficulty for rural Africa is that the regular laboratory tests are expensive and require sophisticated laboratories that are often only available in cities - many hours' drive away from the villages where people live.
The trial results show the regular tests have either no benefit or very little benefit to survival rates.
The results showed that 90% of people who received anti-viral drugs and three-monthly lab testing were still alive after five years compared with 87% of people who received the drugs without undergoing regular testing.
If regular laboratory tests are not needed, doctors say it will be much easier and cheaper to give treatment in village clinics - rather than making patients travel to cities, where most treatment in Africa is concentrated.
Practitioners say with trained healthcare workers they can provide close supervision and support, and give HIV treatment to many more patients close to where they live.
Dr Mugyenyi told the BBC Network Africa: "I would describe [this study] as a breakthrough, because we now understand that the intensive laboratory tests which are routinely done in the West only bring marginal benefits.
"We could actually do nearly as well by very good clinical monitoring of patients, making sure that trained healthcare providers look at their symptoms and signs and determine whether treatment needs to be changed or whether they need to have any modification in their care and treatment."
British International Development Minister Mike Foster said that while anti-retroviral treatment saves lives, the cost of the accompanying laboratory tests "significantly reduces the number of people that this treatment can reach".
"Crucially, the money saved from paying for these tests could enable more people to safely receive treatment, including those who for whatever reason are unable to travel to the laboratories."