Skip Navigation U.S. Department of Health and Human Services
Agency for Healthcare Research Quality
Archive print banner

Pharmaceutical Research

This information is for reference purposes only. It was current when produced and may now be outdated. Archive material is no longer maintained, and some links may not work. Persons with disabilities having difficulty accessing this information should contact us at: Let us know the nature of the problem, the Web address of what you want, and your contact information.

Please go to for current information.

Laboratory drug monitoring of outpatients taking long-term medications could be improved

Patients taking long-term medications such as cholesterol-lowering statins and blood-thinning warfarin should be monitored for drug-related problems via laboratory tests. Yet, lapses in such monitoring among outpatients are common, according to a study supported by the Agency for Healthcare Research and Quality (Contract No. 290-00-0015). Among patients taking an average of nine medications each in 2001, nearly half did not receive one or more recommended laboratory tests to monitor drug safety.

Researchers examined claims data from two HMOS to determine rates of missed laboratory tests in 1999, 2000, and 2001 in patients receiving certain chronic medications for which specific laboratory monitoring is recommended. The total patients studied each year ranged from about 30,000 to 37,000.

Among these patients, 47 percent in 1999, 45 percent in 2000, and 44 percent in 2001 did not receive one or more laboratory tests recommended for safety monitoring. For example, 22 to 27 percent of patients taking statins, which can impair liver function, did not receive a liver function test during a 12-month period. Even when doctors believe laboratory monitoring is clinically important, they may be hampered by the patient not accessing health care, lack of time during patient visits, not having easy access to records of the patient's current drug regimen, and lack of tracking tools such as computerized reminders for the physician or mailed reminders to the patient.

More details are in "Laboratory safety monitoring of chronic medications in ambulatory care settings," by Judith S. Hurley, M.D., R.D., Melissa Roberts, M.S., Leif I. Solberg, M.D., and others, in the Journal of General Internal Medicine 20, pp. 331-333, 2005.

Return to Contents
Proceed to Next Article

The information on this page is archived and provided for reference purposes only.


AHRQ Advancing Excellence in Health Care