Biological diagnosis of primary aldosteronism: summary of new French and international guidelines

The biological diagnosis of primary aldosteronism (PA) is a real challenge in clinical laboratories. First, PA is a major cause of secondary hypertension, and more widespread screening is currently recommended. In addition, the recent development of automated and mass spectrometry tests has made it necessary to determine the most appropriate cutoff values in clinical studies. New French and international guidelines will play an important role in the standardization of PA diagnosis. The first diagnostic step is to measure the aldosterone to renin ratio (ARR), which is widely considered the best screening test. The preanalytical phase is crucial to properly interpret the ARR, and rigorous testing conditions must be observed to improve the diagnostic efficiency. The choice of the most appropriate cutoff value for ARR is a real concern in laboratories due to variability between methods. The second step of PA diagnosis aims to rule out false-positive ARRs using one or more dynamic confirmatory tests based on aldosterone suppression. Finally, the third step involves adrenal venous sampling to distinguish between unilateral and bilateral disease.