Clinical calculator summary
Original 1990 Jacobs RMI-I
Clinical calculator summary
Original 1990 Jacobs RMI-I
A multiplicative preoperative index combining ultrasound findings, menopausal status, and serum CA125.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the original RMI-I value and >200 discrimination threshold without converting it into a malignancy probability or treatment rule.
- Population:
- Patients with a pelvic mass undergoing preoperative discrimination in a cohort resembling the original 1990 study.
- Factors:
- Five named ultrasound findings, Menopausal status, Unrounded serum CA125
- Reference:
- Jacobs et al. Br J Obstet Gynaecol. 1990;97(10):922-929. doi:10.1111/j.1471-0528.1990.tb02448.x.
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RMI (Risk of Malignancy Index)
U/mL
Clinical Context & Background
This calculator reproduces the original 1990 Jacobs Risk of Malignancy Index I (RMI-I). It multiplies the ultrasound score (U), menopausal multiplier (M), and unrounded serum CA125 value: RMI-I = U x M x CA125.
The five ultrasound findings are Multilocular cyst, Solid areas, Bilateral lesions, Ascites, Intra-abdominal metastases. Zero findings gives U=0, one finding gives U=1, and two to five findings gives U=3. Premenopausal status gives M=1 and postmenopausal status gives M=3. Postmenopausal means more than one year since the final menstrual period, or age over 50 years after hysterectomy.
The original discrimination threshold is RMI-I >200. Exactly 200 does not exceed it. The original publication did not define <25, 25-200, and >200 probability tiers. The historical 85% sensitivity and 97% specificity at the >200 threshold came from the 143-patient derivation cohort and are not individualized probabilities.
Use RMI-I only for preoperative assessment of a pelvic mass. It is not an ovarian-cancer screening test, recurrence or surveillance tool, post-treatment assessment, malignancy probability, treatment recommendation, or referral directive.
Formula Logic
Original 1990 RMI-I: RMI = U x M x CA125, where U is 0, 1, or 3 from the number of five ultrasound findings and M is 1 before menopause or 3 after menopause. The original threshold is RMI >200; exactly 200 does not exceed it.Reference Data
| Raw RMI-I | Original 1990 threshold interpretation |
|---|---|
| <=200 | Original discrimination threshold not exceeded |
| >200 | Original discrimination threshold exceeded |
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
When To Use
- Use during preoperative evaluation of an established pelvic mass.
- Enter the unrounded CA125 result and count the five named ultrasound findings.
How To Interpret
- Calculate U x M x CA125 using the original multipliers.
- A raw value greater than 200 exceeds the original threshold; exactly 200 does not.
- Historical sensitivity and specificity describe the derivation cohort and are not patient-specific probabilities.
What To Do Next
- Interpret the index alongside imaging, examination, laboratory context, and specialist clinical judgment.
Limitations
- Not for screening asymptomatic populations, recurrence, surveillance, or post-treatment reassessment.
- Does not diagnose malignancy or prescribe treatment or referral.
- The original cohort was small and historical; performance may differ in other populations.
Validated Population
143 patients with pelvic masses in the original 1990 derivation study: 101 benign and 42 malignant masses.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Three source-backed cases passed through visible production controls at RMI-I 35, exact threshold 200, and RMI-I 315.
- The former valid-result render crash was absent; all results and strict >200 classifications rendered normally.
- No unexpected N/A, literal undefined value, stale control, unsupported gauge, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/rmi-ovarian-2026-08-03.json.
: Local browser remediation verified; production retest pending
- Corrected the result trace method from unsupported `formula` to registered `equation`; the original RMI-I multiplication and strict >200 comparison were unchanged.
- Ten local visible-browser cases passed across menopausal and ultrasound multipliers, equality and just-below/above threshold values, zero-result branches, required-field feedback, and reset/repeat behavior.
- The original production crash remains open until deployment and public revalidation.
Local diagnostic evidence is retained in validation/browser-production/rmi-ovarian.local-remediation.json.
: Production browser validation
- Ten source-backed cases were exercised on the public production route through visible browser controls; 1/10 case records passed their expected-versus-observed assertions across 12 visible submissions.
- Overall browser status: failed-runtime-console. critical: Every complete valid submission crashed the production calculator into an empty error boundary before any RMI-I result rendered; the console reported TypeError: Cannot read properties of undefined (reading 'map'). | medium: Production emitted minified React error #418 during each route load.
- Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.
Case-level production evidence is retained in validation/browser-production/rmi-ovarian.json.
: Browser input adapter corrected and reverified
- Accepted finite number values already normalized by the shared calculator form while retaining strict malformed-input rejection.
- No equation, cutoff, unit, classification, or applicability rule changed; calculator-specific verification and the calculator-wide browser-input audit passed.
: Full validation test
- 320/320 equation, equality-boundary, decimal, strict-input, UI/reset, trace, wording, immutability, registry, and no-panel checks passed with zero score or classification mismatches.
- Scope is the original 1990 preoperative RMI-I for pelvic masses; no registered master panel calculates RMI-I or inherits this status.
: Calculation and input-contract correction
- Locked RMI-I to U x M x unrounded CA125 and the original raw >200 threshold; exactly 200 does not exceed the threshold.
- Removed favorable defaults, direct multiplier codes, unsafe coercion, missing/extra-field acceptance, nonfinite values, unsupported <25/25-200 tiers, probability claims, and referral directives.
- Added the five named ultrasound findings, menopause definition, immutable input snapshot, three-factor multiplication trace, matched threshold row, and historical derivation-cohort wording.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
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Frequently Asked Questions
When should RMI (Risk of Malignancy Index) be used?
Use it for patients undergoing ovarian, cervical, endometrial, or gestational-trophoblastic risk and staging assessment when all required inputs and the intended clinical setting are confirmed.
Can RMI (Risk of Malignancy Index) determine treatment by itself?
No. Interpret the result with the cited evidence, complete clinical assessment, current guidelines, and patient-specific goals.
Evidence-based oncology decision support. Verify with clinical guidelines.