An article in Archives of Internal Medicine (2009;169(12):1123-1129) reveals that about 1 in 14 abnormal outpatient test results are either not reported to the patient or the report to the patient is not documented. The article summarizes a study consisting "of a retrospective medical record review of 5434 randomly selected patients aged 50 to 69 years in 19 community-based and 4 academic medical center primary care practices."
Read an abstract of the article here.