We appreciate the issues raised by Dr. Herman and colleagues regarding follow-up of living kidney donors with treated hypertension. They underscore dilemmas faced by all transplant programs. At some point, each must identify criteria consistent with its population and its interpretation of best medical practices. Most criteria are subject to varied opinions and can be controversial when data are sparse. Several questions addressed measurement of blood pressure (BP), which we discuss elsewhere (1). Our data support the observations of Odzemir that classification of BP differs between ambulatory monitoring (ABPM) and “office” readings. Small differences result in large classification errors when patients are near a specific “cutoff” level. This is most common in older donors. No initial pressure in our study was absolutely excluded. However, we aimed to achieve “normal” levels (defined as <140/90 mmHg by an RN) using a “simple regimen,” defined as lifestyle measures and an angiotensin receptor blocker with or without a thiazide. Subjects requiring more therapy (three or more drugs) and/or having other disqualifiers (glucose intolerance, low GFR, abnormal structure, or microalbuminuria) were among those not accepted. No systematic evaluation of the retina or LVH was undertaken. ABPM measurements were obtained overnight for 18 hr as we have described (2) to obtain awake and nocturnal readings without interfering with daytime tests. These include CT angiography and others that affect BP. These intervals achieve more than 90% concordance with the entire awake period of a 24 hr monitor, as others have established (3,4). A small time-of-day effect (2–4 mm Hg higher) in the afternoon was considered acceptable. For BP classification, the awake period (normal <135/85 mm Hg) is an accepted standard. Nocturnal pressures and day–night variation are presented separately in our report. If we had averaged all pressures recorded, lower overall pressures would have been observed due to the nocturnal decline. These points, of course, are tangential to the broader issue: how and what criteria should be applied for selection of living kidney donors? Some “historical” criteria may no longer apply. These authors note that previous studies suggest that subsequent “hypertension” was more common with higher predonation BP (i.e. 160/95 mmHg). Newer population-based studies demonstrate that pressure rises with age in the U.S. More than 75% of those above age 65 now have “hypertension,” the threshold of which has been lowered to 140/90 mmHg. The Joint National Commission (JNC 7) emphasizes that the lifetime risk of hypertension exceeds 90% for someone reaching age 55 with normal pressures (5). Hence, nearly everyone will become “hypertensive,” regardless of whether they undergo donor nephrectomy. Early identification and treatment of hypertensive donors initiates care that might be delayed otherwise. Fortunately, we are not truly breaking new ground. Pressures acceptable in 1987 (160/95 mm Hg) were higher than those in our “hypertensive donors.” Experience with more than 47,000 donors since 1987 is reassuring in that neither adverse mortality nor renal disease risk has been identified, despite numerous studies. We agree that changes in demographics and life expectancy limit applying previous experience to current kidney donors. It is essential to improve follow-up care and data collection. Blood pressure is but one of the criteria undergoing careful review. We believe it is paramount for active transplant centers to develop practice parameters and monitor their results closely, as we are doing. Stephen C. Textor Sandra J. Taler Nancy Driscoll Timothy S. Larson James Gloor Matthew Griffin Fernando Cosio Thomas Schwab Mikel Prieto Scott Nyberg Michael Ishitani Mark Stegall Department of Medicine Division of Nephrology and Hypertension Department of Transplant Surgery and Transplant Center Mayo Clinic Rochester, MN