Protocol

Units

Aldosterone

Cortisol

Data Entry

Inferior Vena Cava (IVC) / Peripheral Peripheral Reference · 0 samples

Sample	Aldo (pg/mL)	Cortisol (µg/dL)	A/C Ratio	Incl.

A/C Ratio Used in Calculation (included samples) Multiple values are averaged. To use a single value, enter one sample or toggle off the others.

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Right Adrenal Vein Samples · 0 included

Sample	Aldo (pg/mL)	Cortisol (µg/dL)	A/C Ratio	Incl.

A/C Ratio Used in Calculation (included samples) Multiple values are averaged. To use a single value, enter one sample or toggle off the others.

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Left Adrenal Vein Samples · 0 included

Sample	Aldo (pg/mL)	Cortisol (µg/dL)	A/C Ratio	Incl.

A/C Ratio Used in Calculation (included samples) Multiple values are averaged. To use a single value, enter one sample or toggle off the others.

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Results

Awaiting sample data — results will appear here once values are entered.

Dominant Side

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Selectivity Index (SI) Threshold: ≥ 2.0

Right SI

○ No data

Left SI

○ No data

Lateralization Index (LI) ≥ 4.0 lateralized | 2.0–3.9 borderline | < 2.0 bilateral

LI (Higher ÷ Lower A/C)

○ No data

Contralateral Suppression (CSI) < 1.0

CSI (Contralateral ÷ IVC A/C)

○ No data

Copies a brief summary suitable for pasting into a clinical note

Reference Thresholds

SI (unstimulated) ≥ 2.0

SI (cosyntropin-stimulated) ≥ 3.0

LI lateralized ≥ 4.0

LI borderline ≥ 2.0

LI bilateral (derived from borderline) < 2.0

CSI suppression < 1.0

ES Guidelines 2016

References

Funder JW, Carey RM, Mantero F, et al. The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2016;101(5):1889–1916.
Endocrine Society clinical practice guideline for primary aldosteronism management. Discusses AVS lateralization criteria; specific numeric cutoffs for SI, LI, and CSI are detailed in Rossi et al. (2014) below.
Adler GK, Stowasser M, Correa RR, et al. Primary Aldosteronism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2025;110(9):2453–2495. doi:10.1210/clinem/dgaf284
Most recent Endocrine Society update reaffirming AVS as gold standard for lateralization.
Rossi GP, Auchus RJ, Brown M, et al. An Expert Consensus Statement on the Use of Adrenal Vein Sampling for the Subtyping of Primary Aldosteronism. Hypertension. 2014;63(1):151–160. doi:10.1161/HYPERTENSIONAHA.113.02097
Primary source for SI, LI, and CSI numeric thresholds used in this calculator (SI ≥2.0/3.0, LI ≥4.0, CSI <1.0).
Vonend O, Ockenfels N, Gao X, et al. Clinical impact of strict criteria for selectivity and lateralization in adrenal vein sampling. Eur J Endocrinol. PMID: 27376419
Retrospective review of 73 AVS procedures validating strict SI and LI cutoffs.

🔒 Privacy & Data

Disclaimer: This tool is intended to support — not replace — clinical judgment. It does not provide medical advice, diagnosis, or treatment recommendations, and is not a substitute for consultation with a qualified healthcare provider. Threshold values may vary by institution and protocol. This calculator applies the most widely cited published guideline thresholds, and users may adjust thresholds to match institutional protocol. Results must always be interpreted by a qualified clinician in the context of the patient's full clinical picture, including imaging, biochemistry, comorbidities, and surgical candidacy. This calculator should not be used as the sole basis for clinical decision-making.

Changelog

AVS Calculator — Version History

v1.6 April 2026

App logo — vein branch icon added to header and browser tab favicon
IVC Add Sample button — now consistent with adrenal vein sections
Excluded sample flagging — visual notice when samples are toggled off
Reset All button — more prominent with red hover state
Methods modal — explains SI, LI, and CSI formulas with equations
Cite This Tool modal — APA, AMA, and Vancouver formats with one-click copy
Version number badge on every printed report
Date and time auto-populated on clinical reports and patient summaries
Guideline preset badge on printed report
SEO improvements — meta tags, Open Graph, JSON-LD structured data
Report headers: Adrenal Vein Sampling Calculator on left, avsresults.com on right
About:blank suppressed from report footers
Patient summary page breaks and font size optimized

v1.5 March 2026

Multilingual patient summaries — English, Spanish, Mandarin, Korean, Farsi, Russian
Language pill selector in print modal
SI calculation corrected — now uses adrenal cortisol ÷ IVC cortisol
Calculation worksheet with per-sample averages for aldo, cortisol, and A/C ratio
Report restructured — one page per section with patient label strips
Print layout optimized for single-page sections
Cloudflare Web Analytics added (cookieless)
Copyright notice added
"Endocrine Society" replaced with "ES Guidelines" in labels
Unit label bug fixed — µg/dL no longer renders as mg/dL in reports

v1.4 March 2026

Clinical Reports modal with section checkboxes (Summary, Worksheet, Patient Summary)
Single print window with page breaks between selected sections
Patient-Friendly Summary merged into Clinical Reports dropdown
Calculation worksheet with index derivation table
Report page order restructured

v1.3 March 2026

Patient-Friendly Summary with plain-language interpretation
PHI removed — patient name/MRN fields replaced with label box
Feedback form via Formspree
Session timestamp in results panel
On-screen interpretation cards
Input validation with shake animation
Outlier warning for samples deviating >50% from section average
Clear section button per vein

v1.2 March 2026

Multi-sample support per vein (up to 8 samples)
Toggle to include/exclude individual samples
Unit conversion — aldosterone (pg/mL, ng/dL, pmol/L) and cortisol (µg/dL, nmol/L, ng/mL)
Cosyntropin-stimulated protocol support
Customizable threshold inputs
Guideline presets — ES 2016, Adler 2025, Rossi 2014

v1.0 March 2026

Initial release
SI, LI, and CSI calculation
IVC, right, and left adrenal vein inputs
Clinical report export

Calculation Methods

All calculations are performed locally in your browser. No data is transmitted or stored.

Selectivity Index (SI)

Confirms adequate adrenal vein catheterization. Calculated as adrenal vein cortisol divided by IVC cortisol:

SI = Adrenal Vein Cortisol ÷ IVC Cortisol

Thresholds: ≥2.0 (unstimulated) or ≥5.0 (cosyntropin-stimulated) per ES Guidelines. If multiple samples are entered, cortisol values are averaged across included samples before division.

Lateralization Index (LI)

Compares cortisol-corrected aldosterone (A/C ratio) between the dominant and non-dominant adrenal veins:

LI = (Dominant Aldo ÷ Dominant Cort) ÷ (Non-Dominant Aldo ÷ Non-Dominant Cort)

A/C ratios are calculated per sample first, then averaged across included samples. The side with the higher average A/C ratio is designated dominant. Threshold: ≥4.0 (stimulated) per ES Guidelines.

Contralateral Suppression Index (CSI)

Assesses suppression of aldosterone in the non-dominant gland relative to IVC:

CSI = (Non-Dominant Aldo ÷ Non-Dominant Cort) ÷ (IVC Aldo ÷ IVC Cort)

A CSI <1.0 indicates contralateral suppression, supporting unilateral disease. Used in conjunction with LI.

Multi-Sample Averaging

When multiple samples are entered for a vein, A/C ratios are calculated for each sample individually (Aldo ÷ Cort per sample), then averaged across included samples. This preserves per-sample accuracy and is consistent with published multi-sample AVS methodology. Excluded samples are omitted from all averages.

Guideline References

Funder JW et al. J Clin Endocrinol Metab. 2016;101(5):1889–1916.
Adler GK et al. J Clin Endocrinol Metab. 2025;110(9):2453–2495.
Rossi GP et al. Hypertension. 2014;63(1):151–160.

Selectivity Index (SI)

Lateralization Index (LI)

Contralateral Suppression Index (CSI)

Multi-Sample Averaging

Guideline References

APA

AMA

Vancouver