Abstract

AZPIROZ, MB et al. Laboratory Role in the Diagnosis of Primary Aldosteronism. Rev. argent. endocrinol. metab. [online]. 2015, vol.52, n.4, pp.204-214. ISSN 1851-3034.

Primary aldosteronism is nowadays considered the cause of 8 to 12 % cases of hypertension. The increase in its prevalence is due to changes in diagnostic criteria. Initial screening is performed in the laboratory by obtaining the aldosterone to plasma renin activity ratio, for which strict preanalytical conditions are required, including; supine or upright posture; interaction of therapeutic drugs which may alter results; sample extraction and conservation, among others. Given the high variability in the measurement of plasma renin activity and its complexity (RIA), the use of the aldosterone to renin concentration ratio is proposed (where renin concentration is determined by an automated immunoassay), although no consensus has been reached in this matter. The screening method is essential to primarily identify those patients who should be further studied, and it influences the statistics on actual prevalence of primary aldosteronism. Once cutoff values have been determined for each laboratory, patients with positive screening results must be further submitted for confirmation tests, such as salt-loading test or fludrocortisone suppression test, in which the autonomous secretion of aldosterone is confirmed. Then, the cause of the excessive aldosterone production must be determined. The most common are aldosterone producing adenoma and bilateral adrenal hyperplasia. Early diagnosis allows for the correct treatment, minimizing comorbidities caused by hypertension and by vascular and cardiac remodelation due to the excess of aldosterone. Classic treatment for hypertension is not always useful in patients with primary aldosteronism; this is why it is important to know how to diagnose the underlying pathology.

Keywords : Aldosterone; Plasma renin activity; Primary aldosteronism; Renin.

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