We agree with Dr Kuhlmann that excessive testing should not be performed if it does not affect clinical management. Whereas there is little rationale for widespread CSF analysis as a screening measure for AD in the general population in the absence of effective treatments, we believe that this diagnostic measure has value now in at least 3 situations: (1) when a definitive diagnosis of AD may help a patient with cognitive impairments make major decisions regarding activities of daily living, planning for the future, or end of life care prior to the onset of severe cognitive impairment; (2) to clarify whether a person may have another medical condition such as normal pressure hydrocephalus, depression, or vascular ischemia that has some overlap with AD in terms of clinical presentation but requires different medical management; and (3) as a test for increasing the likelihood that individuals enrolled in experimental clinical trials have the underlying pathologic abnormalities being targeted by the treatment being investigated.
Growdon JH, Herskovits AZ. Primum non nocere—Reply. Arch Neurol. 2011;68(3):395-399. doi:10.1001/archneurol.2011.22