Our data suggest that TDM-guided screening is a useful strategy for diagnosing PA in the TRH population. Since previous studies have indicated that hypokalemia was present in only 14% to 48% of patients with PA, the current Endocrine Society guidelines advocate routine screening for PA in all patients with TRH. In contrast, the 2008 AHA position statement recommends investigation for PA only in adherent patients with TRH. However, the cost of nonselective screening and confirming presence for PA in patients with false-positive screening tests may be a substantial burden, considering the rapid rise in prevalence of TRH from 16% in 1998 to 2004 to 28% in 2005 to 2008 according to the National Health and Nutrition Examination Survey.