Formula · Jacobs et al. BJOG 1990
RMI = U × M × CA‑125
U
0 · 1 · 3
Ultrasound
M
1 · 3
Menopausal
CA-125
U/mL
Serum level
1
Menopausal Status (M)
Always known from history — complete first
M = 1
Pre-menopausal
M = 3
Post-menopausal
Definition (RCOG GTG-62)
Post-menopausal = ≥12 months of amenorrhoea · surgical menopause · FSH >40 IU/L if uterus absent
2
CA-125 Serum Level
Lab result — typically available before imaging
U/mL
Normal: <35 U/mL · Elevated in ~80% of advanced epithelial OV CA · Not specific in isolation — interpret within full RMI context
✓
Ultrasound Features (U)
Review scan last · Defaults to U=0 if none selected
Auto-calculated score
U = 0
no features
U=0
No features
U=1
One feature
U=3
Two or more
🔍
Suspicious Ultrasound Features
Jacobs 1990 · RCOG GTG-62 · IOTA · Tap ▼ for evidence
Complete all steps
Menopausal status + CA-125 required.
US features default to U=0 if none selected.
US features default to U=0 if none selected.
Step 1: M
Step 2: CA-125
Step 3: US ✓
📊 Validated Risk Thresholds
RMI < 200
LOW RISK
Manage in general gynecology · RCOG GTG-62
RMI ≥ 200
HIGH RISK
Refer to gynecologic oncology MDT · RCOG GTG-62
⚠️ Note: NICE CG122 recommends referral at RMI ≥ 250. RCOG GTG-62 uses ≥ 200. This tool applies the more conservative RCOG threshold. Always follow your local institutional protocol.
Validated Performance (Van Calster 2016)
~85%
Sensitivity
~97%
Specificity
≥200
RCOG Cutoff