Must RAAS-modifying drugs be withdrawn for the diagnosis of primary aldosteronism?

Several classes of antihypertensive drugs which act on the renin-angiotensin-aldosterone-system (RAAS) change the measurements in blood of aldosterone or renin, and hence the derived aldosterone-renin-ratio. Since guideline-recommended thresholds of this ratio are used for diagnosing primary aldosteronism, it has been common practice to withdraw potentially interfering drugs several weeks prior to diagnostic tests, in order to reduce the risk of false-positive and false-negative results. This debate highlights two opposing views on the necessity for such withdrawal. The Pro-side of the debate emphasizes the importance of an accurate diagnosis to achieve optimal targeted treatment results. The Con-side accentuates the importance of feasibility, safety and costs of routine adjustment of medication. The data available to evaluate the balance of benefit versus risk of these diagnostic approaches have considerable limitations. Prospective outcome studies of newer tests and treatments present an opportunity to define the optimal strategy for maximizing accurate diagnoses of primary aldosteronism.