The cause of CFS, also known as myalgic encephalomyelitis (ME), post-viral fatigue syndrome (PVFS), is not yet known and its symptoms are broad, ranging from fatigue, pain, muscle weakness, and depression to digestive disturbances, immune system weakness, and breathing problems. Moreover, there is no simple diagnostic test for the disease and patients often rely on a sympathetic physician to recognise the problem, but who, nevertheless, does not necessarily have the tools to offer a definitive answer nor an effective treatment. An objective clinical diagnostic test would make understanding and treating this disease far easier. Japanes researchers have now used a type of infra-red spectroscopy to distinguish between plasma from CFS patients and healthy volunteers. They reckon a non-invasive test will be available soon.