Screening for primary aldosteronism using the newly developed IDS-iSYS® automated assay system

Figures

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  Fig. 1. Recruitment Schematic.

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  Fig. 2. Receiver Operator Characteristic (ROC) curves for direct renin concentration (DRC) (mIU/L), plasma aldosterone concentration (PAC) (pmol/L) & aldosterone:renin ratio ARR (pmol/mIU) in the diagnosis of primary aldosteronism for male and female participants both individually and together. AUC: area under the curve (optimum=1.0 the curve will reach the upper left corner of the plot); when the variable under study cannot distinguish between those with and without disease the AUC will be equal to 0.5 (the ROC curve will coincide with the diagonal). *=cut-off point.

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  Fig. 3. Traffic Light plot: green illustrates the absolute values for DRC, PAC and ARR at which study participants in our cohort did not have PA (i.e. PA is highly unlikely), orange represents the absolute values for DRC, PAC and ARR at which some participants had and others did not have PA (i.e. PA indeterminate), orange with shading represents “No Data” and red represents the absolute values for DRC, PAC and ARR at which all participants had PA (i.e. PA highly likely). For example, for DRC (total cohort), all values >14.2 mIU/L are not PA, all values ≤3.5 mIU/L are PA, with values >3.5 mIU/L and ≤14.2 mIU/L indeterminate for PA. For ARR (total cohort), all values <37.7 pmol/mIU are not PA, all values ≥37.7 pmol/mIU and ≤113.6 pmol/mIU are indeterminate for PA, and all values >113.6 pmol/mIU are PA. The junction of the red and orange bar represents the value for the test at which it is 100% specific. The junction of the green and orange bar represents the value for the test at which it is 100% sensitive. Once validated in other cohorts, traffic light plots maybe a useful tool to aid in the interpretation of DRC, PAC and ARR. Abbreviations as Fig. 2.

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  Fig. 4. IDS-iSYS® DRC, PAC and ARR values observed in primary aldosteronism (PA, n=16), healthy volunteers (HV, n=266), healthy females taking the oral contraceptive pill (OCP, n=15), patients with essential Hypertension (EH, n=21), EH+Type 2 diabetes mellitus (T2DM, n=107) and non-PA adrenal (adrenal cortical carcinoma, ACC; Addison's disease, AD; phaeochromocytoma & paraganglioma, PPGL) pathologies (n=12). Abbreviations DRC, PAC and ARR as Fig. 2.