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Linking lab and pharmacy databases can help identify patients who don't undergo followup for abnormal tests

Although concerns about patient safety have mostly focused on medication errors, diagnostic errors represent an important and frequent problem. Timely followup of abnormal laboratory test results is critical to diagnosing medical problems. Linking laboratory and pharmacy databases could help to identify patients who don't undergo followup for abnormal test results, according to a recent study supported by the Agency for Healthcare Research and Quality (HS11552).

Researchers led by Gordon D. Schiff, M.D., of Rush-Presbyterian-St. Luke's Medical Center, downloaded thyroid stimulating hormone (TSH) test results for 2 consecutive years from a laboratory database. They then linked this database with a pharmacy database to screen for patients who were not receiving levothyroxine and had elevated TSH levels, indicating abnormally low levels of the thyroid hormone, thyroxine (hypothyroidism). Patients with elevated TSH levels lacking prescriptions for levothyroxine were followed up by telephone and record review.

During the 2-year period, 982 (2.7 percent) of 36,760 patients tested for TSH level had elevated TSH levels. Of these, 177 patients (18 percent) had no recorded levothyroxine prescriptions. The investigators were able to contact 123 of these patients and found that 12 patients in 2000 and 11 patients in 2001 were unaware of their abnormal test results or a diagnosis of hypothyroidism. The investigators were unable to reach another 5.5 percent of patients with elevated TSH levels, who also may have been unaware of their test results. Linking laboratory and pharmacy databases also uncovered other quality issues, such as undertreatment with levothyroxine (elevated TSH levels despite treatment), delays in therapy adjustment, and lack of patient adherence to treatment.

See "Missed hypothyroidism diagnosis uncovered by linking laboratory and pharmacy data," by Dr. Schiff, Seijeoung Kim, Ph.D., Nela Krosnjar, and others, in the March 14, 2005, Archives of Internal Medicine 165, pp. 574-577.

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