Liquid Chromatography-Tandem Mass Spectrometry Outperforms Radioimmunoassay in Guiding Surgical Decisions Based on Adrenal Venous Sampling in Primary Aldosteronism

Article information

Endocrinol Metab. 2025;40(6):1002-1011

Publication date (electronic) : 2025 July 1

doi : https://doi.org/10.3803/EnM.2024.2237

, Chien-Wei Huang ³^,⁴, Chin-Chen Chang^,¹^,⁵

, Guan-Yuan Chen ⁵, Jia-Zheng Huang ¹, Pin-Chen Chen ¹, Te-I Weng ⁵, Kao-Lang Liu ¹, Vin-Cent Wu ⁶, Yen-Hung Lin ⁶, on Behalf of the TAIPAI Study Group

¹Department of Medical Imaging, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan

²Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan

³Division of Nephrology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

⁴School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan

⁵Department and Graduate Institute of Forensic Medicine, National Taiwan University College of Medicine, Taipei, Taiwan

⁶Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan

Corresponding author: Chin-Chen Chang. Department of Medical Imaging, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 100225, Taiwan Tel: +886-2-23123456, Fax: +886-2-2322-4552, E-mail: macotocc@gmail.com

Received 2024 November 6; Revised 2025 April 6; Accepted 2025 April 23.

Abstract

Background

Adrenal venous sampling (AVS) is essential for diagnosing unilateral aldosterone oversecretion in primary aldosteronism (PA). Traditionally, AVS relies on radioimmunoassay (RIA) to measure plasma aldosterone concentration (PAC), although RIA has limited specificity and considerable variability. This study evaluated the role of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in AVS and its impact on clinical outcomes.

Methods

Among 230 patients with PA (May 2020 to April 2023) who underwent AVS, successful sampling was achieved in 182 patients (79.1%) under unstimulated conditions and 206 patients (89.6%) under stimulated conditions. PAC levels from peripheral and adrenal veins measured by LC-MS/MS were compared with RIA results. Patient outcomes were categorized according to the Primary Aldosteronism Surgical Outcomes criteria.

Results

LC-MS/MS showed significant correlations with PAC levels measured by RIA in AVS (r=0.40 [unstimulated] and r=0.56 [stimulated]; both P<0.001). However, lateralization concordance between RIA and LC-MS/MS was moderate, at only 57.7% (unstimulated) and 64.6% (stimulated). LC-MS/MS identified more unilateral disease than RIA under both unstimulated (61.5% vs. 37.4%, P<0.001) and stimulated conditions (36.4% vs. 9.7%, P<0.001). Patients achieving complete clinical success after adrenalectomy were more accurately identified by LC-MS/MS than RIA under stimulated (55.6% vs. 22.2%, P=0.035), but not in unstimulated conditions.

Conclusion

LC-MS/MS outperformed RIA in identifying unilateral disease, resulting in higher rates of complete clinical success in adrenalectomy patients when surgical decisions were based on LC-MS/MS lateralization results.

Keywords: Adrenal venous sampling; Hyperaldosteronism; Humans; Mass spectrometry

GRAPHICAL ABSTRACT

INTRODUCTION

Primary aldosteronism (PA), characterized by excessive aldosterone secretion, is the most common cause of secondary hypertension. The prevalence of PA among hypertensive patients is approximately 5% to 10% [1] and reaches 20% in individuals with drug-resistant hypertension [2]. PA is associated with a higher risk of cardiovascular events than essential hypertension [3,4]. The treatment for PA primarily depends on subtype classification as either unilateral or bilateral. Surgery is typically indicated for unilateral PA because unilateral adrenalectomy cures hypertension in approximately 30% to 60% of these patients [5,6]. Conversely, long-term therapy with mineralocorticoid receptor antagonists is usually required for bilateral PA [7]. Therefore, accurate diagnosis and precise subtype differentiation in PA are critical for effective clinical management. Currently, direct adrenal venous sampling (AVS) is considered the gold standard diagnostic method for PA subtype differentiation [8-10].

Recently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods have been developed and adopted for routine clinical analysis of several steroid hormones [11,12]. These LC-MS/MS methods offer superior specificity, particularly advantageous in PA diagnosis [13,14]. However, few studies have comprehensively evaluated the performance of LCMS/MS analysis in AVS samples relative to traditional radioimmunoassay (RIA), and data on outcomes following adrenalectomy remain limited. Therefore, this study aimed to compare lateralization results between LC-MS/MS and RIA, as well as 1-year clinical and biochemical success rates, in a cohort of 230 consecutive patients with PA who underwent AVS at a single tertiary referral center.

METHODS

Patient enrollment

We performed a retrospective study consisting of 230 consecutive patients who underwent AVS between May 2020 and April 2023 at our institution. The inclusion criterion was a confirmed diagnosis of PA. Patients for whom AVS was unsuccessful were excluded from this study (n=48 cases for unstimulated AVS; n=24 cases for stimulated AVS). All patients were followed up at our institution until January 2024. AVS blood sample data were obtained for each patient from the Taiwan Primary Aldosteronism Investigators (TAIPAI) database [15]. Ethical approval (202201094RINC) was granted for this study by the Research Ethics Committee of National Taiwan University Hospital, Taipei, Taiwan, on 18 April 2022, and all participants provided written informed consent.

Diagnostic criteria for PA

The diagnosis of PA was made according to the consensus guidelines of the Taiwan Society of Aldosteronism [15]. Plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were quantified using specific RIA kits (PAC: Aldosterone Maia Kit, Adaltis Italia, Bologna, Italy; PRA: DiaSorin, Stillwater, MN, USA). PA was defined as an aldosterone-to-renin ratio (ARR) >35 combined with a positive confirmatory test, such as a captopril challenge test, saline infusion test, or salt loading test. Calcium channel blockers or α-adrenergic blockers were the preferred antihypertensive medications administered prior to screening and confirmatory diagnostic tests. A confirmed PA diagnosis required the following criteria: (1) autonomous excess aldosterone production, indicated by an ARR >35; (2) a TAIPAI score exceeding 60% [16]; and (3) a seated post-saline loading PAC >16 ng/dL or PAC/PRA >35 (ng/dL)/(ng/mL/hr) following a captopril/losartan test.

AVS protocol

Two interventional radiologists (Bo-Ching Lee with 6 years of experience and Chin-Chen Chang with 14 years of experience) performed the AVS procedures. Contrast-enhanced abdominal computed tomography was used to evaluate the anatomy of the right adrenal vein. The catheter tip positioning was confirmed fluoroscopically in the anteroposterior projection by manual injection of 0.5 to 1 mL contrast. Classic adrenal venography confirmed correct catheter placement, validated using an immunochromatographic quick cortisol assay [17,18]. Simultaneous sampling from peripheral and bilateral adrenal veins was conducted to limit aldosterone fluctuations.

After the unstimulated AVS, adrenocorticotropic hormone (ACTH)-stimulated AVS was performed using a 15-minute sampling period following intravenous injection of a 0.25 mg cosyntropin bolus.

Selectivity and lateralization indices for AVS

The selectivity index (SI) was calculated as the cortisol concentration in each adrenal vein divided by the cortisol concentration in the peripheral vein. The lateralization index (LI) was calculated as the aldosterone/cortisol concentration ratio of the dominant side divided by that of the contralateral side. Successful AVS required an SI ≥2.0 bilaterally for unstimulated AVS or ≥ 5.0 bilaterally after ACTH stimulation [19].

To evaluate the performance of LC-MS/MS and RIA, we applied cutoff values of ≥2.0 for unstimulated AVS and ≥2.6 or ≥4.0 after ACTH stimulation [20].

Immunoassay measurement

Serum cortisol concentrations were measured using a chemiluminescent microparticle immunoassay (Architect, Abbott, VA, USA), with intra-assay and inter-assay coefficients of variation (CVs) of 3.3% and 3.4%, respectively, and a limit of detection (LOD) of 8 ng/mL. Plasma aldosterone levels were quantified using the ALDO-RIACT RIA kit (Cisbio Bioassays, Codolet, France) according to the manufacturer’s protocol. The assay has intra-assay and inter-assay CVs of 7.7% and 8.4%, respectively, with an LOD of 0.007 ng/mL.

LC-MS/MS

Aldosterone concentrations in AVS samples were measured by LC-MS/MS using an Agilent 1290 UHPLC (Santa Clara, CA, USA) coupled to a Sciex 6500 Qtrap (Framingham, MA, USA) operating in multiple reaction monitoring mode, following a previously described protocol [14]. Briefly, 100 μL of serum was diluted with 900 μL deionized water, and 5 μL isotope-coded steroid standards were added for quantification. Solid-phase extraction was conducted according to the manufacturer’s instructions. The linearity, sensitivity, accuracy, and precision of the measurements were verified.

Post-adrenalectomy follow-up

The Primary Aldosteronism Surgical Outcomes consensus criteria were applied to assess the clinical and biochemical outcomes of patients with PA undergoing adrenalectomy [21].

Statistical analysis

Categorical variables are presented as frequencies and percentages; continuous variables as means±standard deviations; and skewed continuous variables (e.g., aldosterone and cortisol levels) as medians with interquartile ranges. Bland–Altman plots assessed agreement between the LC-MS/MS and RIA methods. Pearson’s correlation was employed to evaluate correlations between aldosterone levels measured by LC-MS/MS and RIA; aldosterone levels were log₁₀-transformed. Differences in aldosterone levels measured by LC-MS/MS and RIA were evaluated using the Wilcoxon signed-rank test; the paired-sample t test was used to compare log₁₀-transformed values.

The differences in AVS results and surgical outcomes (complete clinical and biochemical success) between the LC-MS/MS and RIA methods were assessed using the McNemar test. Clinical characteristics between patients with concordant and discordant lateralization results by LC-MS/MS and RIA were compared using the chi-square test for categorical variables, the independent- samples t test for normally distributed continuous variables, or the Mann–Whitney U test for non-normally distributed continuous variables. Surgical outcomes (complete, partial, failed) were compared between LC-MS/MS and RIA using the Fisher exact test, assuming independence between methods. SPSS version 25 (IBM, Armonk, NY, USA) was used for statistical analyses; two-sided P values <0.05 were considered significant.

RESULTS

A total of 230 consecutive patients with PA underwent AVS during the study period. Of these, successful unstimulated AVS was performed in 182 patients (79.1%) and successful ACTH-stimulated AVS in 206 patients (89.6%). The demographic characteristics and imaging findings related to PA in patients with successful AVS are presented in Table 1.

Table 1.

Clinical Characteristics of Patients with PA Who Underwent Successful Unstimulated AVS and ACTH-Stimulated AVS

Differences between LC-MS/MS and RIA

The PAC values measured by RIA showed significant correlations with the PAC values measured by LC-MS/MS for both unstimulated AVS (r=0.40, P<0.001) (Fig. 1A) and ACTH-stimulated AVS (r=0.56, P<0.001) (Fig. 1B). The mean difference was −95.5% (95% limits of agreement [LoA], −102.5% to −88.5%) (Fig. 2A) for unstimulated AVS and −112.8% (95% LoA, −118.7% to −106.9%) (Fig. 2B) for ACTH-stimulated AVS. Although PAC measurements by LC-MS/MS in adrenal and peripheral veins correlated significantly with those obtained via RIA, LC-MS/MS consistently yielded higher PAC values compared to RIA for samples from the right adrenal vein, left adrenal vein, and peripheral veins in both unstimulated and ACTH-stimulated conditions (P<0.001) (Table 2).

Fig. 1.

Correlation between aldosterone levels (log10 transformation) measured by liquid chromatography-tandem mass spectrometry (LCMS/ MS) and radioimmunoassay (RIA) methods for unstimulated adrenal venous sampling (AVS) (A) and adrenocorticotropic hormonestimulated AVS (B). IVC, inferior vena cava.

Fig. 2.

Bland–Altman plots showing the agreement between aldosterone levels measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and radioimmunoassay (RIA) methods for unstimulated adrenal venous sampling (AVS) (A) and adrenocorticotropic hormone-stimulated AVS (B). IVC, inferior vena cava.

Table 2.

Comparison of Aldosterone Levels Quantified by RIA and LC-MS/MS Methods for Different Sampling Veins in AVS

LC-MS/MS based lateralization results

Table 3 presents comparisons of AVS lateralization results obtained by RIA and LC-MS/MS methods. For unstimulated AVS, the concordance rate for PA lateralization between RIA and LC-MS/MS was 57.7% (105/182), using a lateralization cutoff of ≥ 2.0. LC-MS/MS identified unilateral PA in 61.5% (112/182) of patients, significantly higher than the 37.4% (68/182) identified by RIA (P<0.001). Clinical characteristics of patients with concordant versus discordant lateralization results based on unsulated AVS (cutoff ≥2.0) showed no significant differences between RIA and LC-MS/MS (Supplemental Table S1).

Table 3.

Differences in the Results of AVS between the LC-MS/MS and RIA Methods

For ACTH-stimulated AVS with a lateralization cutoff of ≥ 2.6, the concordance rate between RIA and LC-MS/MS was 58.3% (120/206). Notably, LC-MS/MS detected lateralization in 46.6% (96/206) of cases compared to only 18.0% (37/206) by RIA (P<0.001).

When applying a more stringent lateralization cutoff of ≥4.0 for ACTH-stimulated AVS, concordance between RIA and LC-MS/MS improved slightly to 64.6% (133/206). LC-MS/MS still identified significantly more cases of unilateral PA (36.4%, 75/206) compared to RIA (9.7%, 20/206; P<0.001). Patients with concordant lateralization results for stimulated AVS were less likely to have hypokalemia and more likely to have adrenal nodules compared with those having discordant results (Supplemental Tables S2, S3).

In summary, LC-MS/MS consistently identified more patients potentially eligible for adrenalectomy among those classified with bilateral disease by RIA.

Post-adrenalectomy surgical outcomes

A total of 88 patients underwent unilateral adrenalectomy based on AVS results and had postoperative follow-up for at least 1 year. Patients achieving complete biochemical success after adrenalectomy were defined as unilateral PA cases who benefited from surgery. Among these unilateral PA patients, lateralization rates were not significantly different between RIA and LC-MS/ MS based on unstimulated AVS (cutoff ≥2.0: 45.8% vs. 55.9%, P=0.286). However, under ACTH-stimulated AVS conditions, RIA identified significantly fewer lateralizations compared to LC-MS/MS at a cutoff ≥2.6 (24.6% vs. 49.3%, P=0.002) and a cutoff ≥4.0 (13.0% vs. 43.5%, P<0.001).

Among patients achieving complete clinical success after adrenalectomy, lateralization rates based on unstimulated AVS (cutoff ≥2.0: 47.6% vs. 57.1%, P=0.727) or ACTH-stimulated AVS with a cutoff ≥2.6 (33.3% vs. 59.3%, P=0.092) were not significantly different between RIA and LC-MS/MS. Nevertheless, using the stricter cutoff of ≥4.0 in stimulated AVS, RIA identified significantly fewer cases with lateralization compared to LC-MS/MS (22.2% vs. 55.6%, P=0.035) (Table 4). These results suggest that LC-MS/MS identifies more patients with unilateral PA who are likely to experience clinical success following unilateral adrenalectomy, particularly when based on ACTH-stimulated AVS results.

Table 4.

Comparison of the Surgical Outcomes of Patients with PA Based on the Results of the LC-MS/MS and RIA Methods

Finally, among patients identified as having unilateral PA by either RIA or LC-MS/MS, post-adrenalectomy outcomes were similar, regardless of whether the cases were detected using unstimulated or ACTH-stimulated AVS (Supplemental Table S4).

DISCUSSION

Due to advances in detection technology, LC-MS/MS is increasingly recognized as the new gold standard for hormone measurement [22]. LC-MS/MS provides high specificity and sensitivity because it identifies the mass-to-charge ratio of substances and simultaneously detects parent and product ions [23]. Consequently, traditional RIA, commonly used to quantify plasma aldosterone, has been replaced by the more reliable and specific LC-MS/MS method in many specialized laboratories [24]. Nevertheless, consensus regarding the diagnostic value of LC-MS/MS methods in AVS remains unclear. In the current study, we assessed the accuracy of LC-MS/MS in measuring aldosterone during AVS, which is recommended for subtyping PA. Our results revealed a significant correlation between LC-MS/MS and RIA for aldosterone measurements in both unstimulated and stimulated AVS. However, LC-MS/MS identified more cases of unilateral disease compared to RIA under both conditions. Additionally, LC-MS/MS identified a greater number of patients likely to achieve biochemical success after unilateral adrenalectomy based on stimulated AVS compared to RIA. These findings indicate that the superior performance of LC-MS/MS in detecting unilateral disease during lateralization assays could result in higher rates of complete biochemical success among patients undergoing adrenalectomy.

RIA assays for aldosterone have several inherent limitations, such as variable specificity and cross-reactivity of antibodies with structurally similar compounds, potentially leading to an overestimation of aldosterone concentrations [25]. Significant discrepancies among different RIA kits have been previously reported [26-28]. Moreover, several studies have demonstrated that aldosterone concentrations measured by LC-MS/MS are generally lower than those obtained by RIA [13,29,30]. In contrast, our study showed that the RIA assay typically yielded lower aldosterone levels than LC-MS/MS, despite a strong correlation between both methods. This divergence might be attributed to the substantially higher aldosterone concentrations in adrenal venous samples compared to peripheral venous samples, potentially reducing the positive bias typically seen with RIA [31,32]. Another explanation could be that stress induced by AVS maneuvers [33] increases aldosterone production without allowing sufficient time for RIA-detectable metabolite formation, narrowing the difference between RIA and LC-MS/MS measurements. Moreover, since approximately one-third of aldosterone circulates in free form and the remainder is bound to proteins [34], RIA—which detects total aldosterone and metabolites—may inadequately measure protein-bound aldosterone, thereby yielding lower results.

Our findings indicate that RIA measurements have lower specificity and accuracy compared to LC-MS/MS, underscoring the necessity for caution when employing RIA, particularly in AVS procedures.

Compared to the significantly reduced lateralization rates identified by RIA, ACTH stimulation had a lesser impact on lateralization detection when utilizing LC-MS/MS-derived LI. Elevated aldosterone levels after ACTH stimulation may exceed the typical detection range of RIA, potentially biasing outcomes. Furthermore, previous studies have indicated that ACTH stimulation exerts dual effects: it increases AVS success rates but simultaneously decreases the difference in aldosterone secretion between bilateral adrenal glands by promoting contralateral secretion [35,36]. Nevertheless, the surgical cure of PA depends fundamentally on identifying unilateral sources via AVS. Our results thus suggest that LC-MS/MS can more effectively identify candidates suitable for unilateral adrenalectomy when RIA would yield inconclusive lateralization results.

This study has several limitations. First, LC-MS/MS assays for aldosterone quantification may exhibit variability due to differences in sensitivity, instrumentation, and equipment setup, potentially causing variations in the lower limit of quantification across institutions. LC-MS/MS analysis necessitates meticulous optimization and harmonization of numerous parameters by experienced technical personnel, along with rigorous quality control [27]. Currently, no established consensus or guidelines exist for implementing LC-MS/MS assays, restricting broader clinical adoption. Furthermore, the initial diagnosis of PA in this study relied on potentially inaccurate RIA results, which could have introduced patient selection bias. Lastly, complete 1-year postoperative follow-up was available for only a subset of patients (n=88); thus, the capability of LC-MS/MS to improve clinical and biochemical outcomes requires validation through additional long-term studies.

In conclusion, although significant correlations between LC-MS/MS and RIA aldosterone measurements were observed for both unstimulated and stimulated AVS, LC-MS/MS demonstrated superior performance in detecting unilateral disease compared to RIA. Consequently, LC-MS/MS may lead to higher rates of complete clinical success among patients undergoing adrenalectomy for PA.

Supplementary Material

Supplemental Table S1.

Comparison of the Clinical Characteristics of Patients with Concordant and Discordant Lateralization Results in RIA vs. LC-MS/MS Based on a LI ≥2

enm-2024-2237-Supplemental-Table-S1.pdf

Supplemental Table S2.

Comparison of the Clinical Characteristics of Patients with Concordant and Discordant Lateralization Results in RIA vs. LC-MS/MS Based on a LI ≥2.6

enm-2024-2237-Supplemental-Table-S2.pdf

Supplemental Table S3.

Comparison of the Clinical Characteristics of Patients with Concordant and Discordant Lateralization Results in RIA vs. LC-MS/MS Based on a LI ≥4

enm-2024-2237-Supplemental-Table-S3.pdf

Supplemental Table S4.

Comparison of the Surgical Outcomes of Patients Identified to Have Unilateral PA Based on RIA or LC-MS/MS

enm-2024-2237-Supplemental-Table-S4.pdf

Notes

CONFLICTS OF INTEREST

No potential conflict of interest relevant to this article was reported.

ACKNOWLEDGMENTS

This work was supported by grants from the Ministry of Science and Technology, Taiwan (MOST-111-2628-B-002-025-MY3).

We express our gratitude to the staff of the Forensic and Clinical Toxicology Center at National Taiwan University College of Medicine and National Taiwan University Hospital for their technical assistance.

AUTHOR CONTRIBUTIONS

Conception or design: B.C.L., C.W.H., Y.H.L. Acquisition, analysis, or interpretation of data: B.C.L., C.C.C., G.Y.C., J.Z.H., P.C.C., T.I.W., Y.H.L. Drafting the work or revising: B.C.L., C.W.H., C.C.C., K.L.L., V.C.W., Y.H.L. Final approval of the manuscript: B.C.L., C.W.H., C.C.C., G.Y.C., J.Z.H., P.C.C., T.I.W., K.L.L., V.C.W., Y.H.L.

References

1. Rossi GP, Bernini G, Caliumi C, Desideri G, Fabris B, Ferri C, et al. A prospective study of the prevalence of primary aldosteronism in 1,125 hypertensive patients. J Am Coll Cardiol 2006;48:2293–300.

2. Douma S, Petidis K, Doumas M, Papaefthimiou P, Triantafyllou A, Kartali N, et al. Prevalence of primary hyperaldosteronism in resistant hypertension: a retrospective observational study. Lancet 2008;371:1921–6.

3. Takeda R, Matsubara T, Miyamori I, Hatakeyama H, Morise T. Vascular complications in patients with aldosterone producing adenoma in Japan: comparative study with essential hypertension. The Research Committee of Disorders of Adrenal Hormones in Japan. J Endocrinol Invest 1995;18:370–3.

4. Milliez P, Girerd X, Plouin PF, Blacher J, Safar ME, Mourad JJ. Evidence for an increased rate of cardiovascular events in patients with primary aldosteronism. J Am Coll Cardiol 2005;45:1243–8.

5. Lumachi F, Ermani M, Basso SM, Armanini D, Iacobone M, Favia G. Long-term results of adrenalectomy in patients with aldosterone-producing adenomas: multivariate analysis of factors affecting unresolved hypertension and review of the literature. Am Surg 2005;71:864–9.

6. TAIPAI Study Group, Wu VC, Chueh SC, Chang HW, Lin LY, Liu KL, et al. Association of kidney function with residual hypertension after treatment of aldosterone-producing adenoma. Am J Kidney Dis 2009;54:665–73.

7. Rossi GP. Diagnosis and treatment of primary aldosteronism. Rev Endocr Metab Disord 2011;12:27–36.

8. Magill SB, Raff H, Shaker JL, Brickner RC, Knechtges TE, Kehoe ME, et al. Comparison of adrenal vein sampling and computed tomography in the differentiation of primary aldosteronism. J Clin Endocrinol Metab 2001;86:1066–71.

9. Young WF, Stanson AW, Thompson GB, Grant CS, Farley DR, van Heerden JA. Role for adrenal venous sampling in primary aldosteronism. Surgery 2004;136:1227–35.

10. Funder JW, Carey RM, Fardella C, Gomez-Sanchez CE, Mantero F, Stowasser M, et al. Case detection, diagnosis, and treatment of patients with primary aldosteronism: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 2008;93:3266–81.

11. Storbeck KH, Gilligan L, Jenkinson C, Baranowski ES, Quanson JL, Arlt W, et al. The utility of ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis. J Chromatogr B Analyt Technol Biomed Life Sci 2018;1085:36–41.

12. Ketha H, Kaur S, Grebe SK, Singh RJ. Clinical applications of LC-MS sex steroid assays: evolution of methodologies in the 21st century. Curr Opin Endocrinol Diabetes Obes 2014;21:217–26.

13. Fuss CT, Brohm K, Kurlbaum M, Hannemann A, Kendl S, Fassnacht M, et al. Confirmatory testing of primary aldosteronism with saline infusion test and LC-MS/MS. Eur J Endocrinol 2021;184:167–78.

14. Chang YL, Chen GY, Lee BC, Chen PT, Liu KL, Chang CC, et al. Optimizing adrenal vein sampling in primary aldosteronism subtyping through LC-MS/MS and secretion ratios of aldosterone, 18-oxocortisol, and 18-hydroxycortisol. Hypertens Res 2023;46:1983–94.

15. Wu VC, Hu YH, Er LK, Yen RF, Chang CH, Chang YL, et al. Case detection and diagnosis of primary aldosteronism: the consensus of Taiwan Society of Aldosteronism. J Formos Med Assoc 2017;116:993–1005.

16. Wu VC, Yang SY, Lin JW, Cheng BW, Kuo CC, Tsai CT, et al. Kidney impairment in primary aldosteronism. Clin Chim Acta 2011;412:1319–25.

17. Daunt N. Adrenal vein sampling: how to make it quick, easy, and successful. Radiographics 2005;25 Suppl 1:S143–58.

18. Yoneda T, Karashima S, Kometani M, Usukura M, Demura M, Sanada J, et al. Impact of new quick gold nanoparticle-based cortisol assay during adrenal vein sampling for primary aldosteronism. J Clin Endocrinol Metab 2016;101:2554–61.

19. Rossi GP, Auchus RJ, Brown M, Lenders JW, Naruse M, Plouin PF, et al. An expert consensus statement on use of adrenal vein sampling for the subtyping of primary aldosteronism. Hypertension 2014;63:151–60.

20. Naruse M, Katabami T, Shibata H, Sone M, Takahashi K, Tanabe A, et al. Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021. Endocr J 2022;69:327–59.

21. Williams TA, Lenders JW, Mulatero P, Burrello J, Rottenkolber M, Adolf C, et al. Outcomes after adrenalectomy for unilateral primary aldosteronism: an international consensus on outcome measures and analysis of remission rates in an international cohort. Lancet Diabetes Endocrinol 2017;5:689–99.

22. Hawley JM, Keevil BG. Endogenous glucocorticoid analysis by liquid chromatography-tandem mass spectrometry in routine clinical laboratories. J Steroid Biochem Mol Biol 2016;162:27–40.

23. Taylor PJ, Cooper DP, Gordon RD, Stowasser M. Measurement of aldosterone in human plasma by semiautomated HPLC-tandem mass spectrometry. Clin Chem 2009;55:1155–62.

24. Juutilainen A, Savolainen K, Romppanen J, Turpeinen U, Hamalainen E, Kemppainen J, et al. Combination of LC-MS/MS aldosterone and automated direct renin in screening for primary aldosteronism. Clin Chim Acta 2014;433:209–15.

25. Burrello J, Monticone S, Buffolo F, Lucchiari M, Tetti M, Rabbia F, et al. Diagnostic accuracy of aldosterone and renin measurement by chemiluminescent immunoassay and radioimmunoassay in primary aldosteronism. J Hypertens 2016;34:920–7.

26. Schirpenbach C, Seiler L, Maser-Gluth C, Beuschlein F, Reincke M, Bidlingmaier M. Automated chemiluminescence-immunoassay for aldosterone during dynamic testing: comparison to radioimmunoassays with and without extraction steps. Clin Chem 2006;52:1749–55.

27. Yin Y, Ma C, Yu S, Liu W, Wang D, You T, et al. Comparison of three different chemiluminescence assays and a rapid liquid chromatography tandem mass spectrometry method for measuring serum aldosterone. Clin Chem Lab Med 2019;58:95–102.

28. Ray JA, Kushnir MM, Palmer J, Sadjadi S, Rockwood AL, Meikle AW. Enhancement of specificity of aldosterone measurement in human serum and plasma using 2D-LC-MS/MS and comparison with commercial immunoassays. J Chromatogr B Analyt Technol Biomed Life Sci 2014;970:102–7.

29. Turpeinen U, Hamalainen E, Stenman UH. Determination of aldosterone in serum by liquid chromatography-tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2008;862:113–8.

30. Baron S, Amar L, Faucon AL, Blanchard A, Baffalie L, Faucard C, et al. Criteria for diagnosing primary aldosteronism on the basis of liquid chromatography-tandem mass spectrometry determinations of plasma aldosterone concentration. J Hypertens 2018;36:1592–601.

31. Le Goff CM, Gonzalez-Antuna A, Peeters SD, Fabregat-Cabello N, Van Der Gugten JG, Vroonen L, et al. Migration from RIA to LC-MS/MS for aldosterone determination: implications for clinical practice and determination of plasma and urine reference range intervals in a cohort of healthy Belgian subjects. Clin Mass Spectrom 2018;9:7–17.

32. Guo Z, Poglitsch M, McWhinney BC, Ungerer JP, Ahmed AH, Gordon RD, et al. Aldosterone LC-MS/MS assay-specific threshold values in screening and confirmatory testing for primary aldosteronism. J Clin Endocrinol Metab 2018;103:3965–73.

33. Chang CC, Lee BC, Liu KL, Chang YC, Wu VC, Huang KH, et al. The influence of the peripheral cortisol fluctuation on the success rate of adrenal venous sampling. Sci Rep 2018;8:2664.

34. Katayama S, Yamaji T. A binding-protein for aldosterone in human plasma. J Steroid Biochem 1982;16:185–92.

35. Rossitto G, Amar L, Azizi M, Riester A, Reincke M, Degenhart C, et al. Subtyping of primary aldosteronism in the AVIS- 2 Study: assessment of selectivity and lateralization. J Clin Endocrinol Metab 2020;105:dgz017.

36. El Ghorayeb N, Mazzuco TL, Bourdeau I, Mailhot JP, Zhu PS, Therasse E, et al. Basal and post-ACTH aldosterone and its ratios are useful during adrenal vein sampling in primary aldosteronism. J Clin Endocrinol Metab 2016;101:1826–35.

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Variable	Unstimulated AVS (n=182)	ACTH-stimulated AVS (n=206)
Male sex	91 (50.0)	108 (52.4)
Age, yr	53.9±11.3	55.0±11.8
Body mass index, kg/m²	25.8±5.9	25.8±5.8
Systolic blood pressure, mm Hg	149.3±22.6	149.8±23.2
Diastolic blood pressure, mm Hg	90.0±14.0	89.7±14.0
Plasma aldosterone concentration, ng/dL	25.0 (16.6–33.6)	23.9 (16.6–32.9)
Plasma renin activity, ng/mL/hr	0.80 (0.33–1.24)	0.79 (0.32–1.25)
Potassium, mEq/L	3.8±0.6	3.8±0.6
Potassium <3.5 mEq/L	48 (26.4)	57 (27.7)
Antihypertensive use, n	2.3±1.9	2.2±2.0
Adrenal CT
Normal	35 (19.2)	35 (17.0)
Unilateral nodules	114 (62.6)	131 (63.6)
Bilateral nodules	33 (18.1)	40 (19.4)
Cortisol, μg/dL
Left adrenal vein	93.6 (35.5–194.7)	583.0 (328.0–778.8)
Right adrenal vein	107.5 (53.6–259.3)	777.6 (548.2–1,048.1)
Peripheral vein	9.7 (7.7–12.9)	15.9 (13.2–17.6)

Plasma aldosterone concentration, ng/dL	RIA	LC-MS/MS	P value
Unstimulated AVS
Left adrenal vein	137 (73–266)	319 (145–738)	<0.001^a
Right adrenal vein	158 (102–269)	446 (224–1,112)	<0.001^a
Peripheral vein	23 (13–37)	182 (73–319)	<0.001^a
Log₁₀ transformed
Left adrenal vein	2.1±0.4	2.5±0.5	<0.001^a
Right adrenal vein	2.2±0.4	2.7±0.5	<0.001^a
Peripheral vein	1.3±0.4	2.2±0.4	<0.001^a
ACTH-stimulated AVS
Left adrenal vein	356 (238–552)	1,706 (616–3,528)	<0.001^a
Right adrenal vein	376 (258–555)	2,184 (693–4,512)	<0.001^a
Peripheral vein	29 (16–49)	195 (93–410)	<0.001^a
Log₁₀ transformed
Left adrenal vein	2.5±0.3	3.2±0.6	<0.001^a
Right adrenal vein	2.6±0.3	3.2±0.6	<0.001^a
Peripheral vein	1.5±0.4	2.4±0.5	<0.001^a

	RIA				P (McNemar)
	Bilateral	Left	Right	Total	P (McNemar)
Unstimulated LC-MS/MS (LI ≥2)	Unstimulated RIA (≥2)				<0.001^a
Bilateral	56 (30.8)	9 (4.9)	5 (2.7)	70
Left	22 (12.1)	28 (15.4)	2 (1.1)	52
Right	36 (19.8)	3 (1.6)	21 (11.5)	60
Total	114	40	28	182
Stimulated LC-MS/MS (LI ≥2.6)	Stimulated RIA (≥2.6)				<0.001^a
Bilateral	99 (48.1)	9 (4.4)	2 (1.0)	110
Left	40 (19.4)	14 (6.8)	1 (0.5)	55
Right	30 (14.6)	4 (1.9)	7 (3.4)	41
Total	169	27	10	206
Stimulated LC-MS/MS (LI ≥4)	Stimulated RIA (≥4)				<0.001^a
Bilateral	123 (59.7)	5 (2.4)	3 (1.5)	131
Left	37 (18.0)	7 (3.4)	0	44
Right	26 (12.6)	2 (1.0)	3 (1.5)	31
Total	186	14	6	206

Surgical outcome	Cutoff value for LI	RIA	LC-MS/MS	P (McNemar)
Complete biochemical success
Successful unstimulated AVS, n=59	2.0	27 (45.8)	33 (55.9)	0.286
Successful ACTH-stimulated AVS, n=69	2.6	17 (24.6)	34 (49.3)	0.002^a
Successful ACTH-stimulated AVS, n=69	4.0	9 (13.0)	30 (43.5)	<0.001^a
Complete clinical success
Successful unstimulated AVS, n=21	2.0	10 (47.6)	12 (57.1)	0.727
Successful ACTH-stimulated AVS, n=27	2.6	9 (33.3)	16 (59.3)	0.092
Successful ACTH-stimulated AVS, n=27	4.0	6 (22.2)	15 (55.6)	0.035^a