to ME/CFS or fibromyalgia. Doctor–patient relations People with CFS face stigma in healthcare settings, and doctors may have trouble managing an illness that lacks a clear cause or treatment. There has been much disagreement over proposed causes, diagnosis, and treatment of the illness. Some doctors believe it is psychological. Most patients are convinced their illness is physical instead, straining doctor-patient relationships. Clinicians may be unfamiliar with CFS, as it is often not covered in medical school. Due to this unfamiliarity, patients may go undiagnosed for years, or be misdiagnosed with mental conditions. A substantial portion of doctors are uncertain about how to diagnose or manage CFS. In a 2006 survey of GPs in southwest England, 75% accepted it as a "recognisable clinical entity," but 48% did not feel confident in diagnosing it, and 41% in managing it. The NAM report refers to CFS as "stigmatized," and the majority of patients report negative healthcare experiences. These patients may feel that their doctor inappropriately calls their illness psychological or doubts the severity of their symptoms. They may also feel forced to prove that they are legitimately ill. Some may be given outdated treatments that provoke symptoms or assume their illness is due to unhelpful thoughts and deconditioning. In a 2009 survey, only 35% of patients considered their physicians experienced with CFS and only 23% thought their doctors knew enough to treat it. Blood donation In 2010, several national blood banks adopted measures to discourage or prohibit individuals diagnosed with CFS from donating blood, based on concern following the 2009 claim of a link between CFS and a retrovirus which was subsequently shown to be unfounded. Organizations adopting these or similar measures included the Canadian Blood Services, the New Zealand Blood Service, the Australian Red Cross Blood Service and the American Association of Blood Banks. In November 2010, the UK National Blood Service permanently deferred ME/CFS patients from donating blood to prevent potential harm to the donor. Donation policy in the UK now states, "The condition is relapsing by nature and donation may make symptoms worse, or provoke a relapse in an affected individual." Controversy Much contention has arisen over the cause, pathophysiology, nomenclature, and diagnostic criteria of CFS. Historically, many professionals within the medical community were unfamiliar with CFS, or did not recognize it as a real condition; nor did agreement exist on its prevalence or seriousness. Some people with CFS reject