🍁 Canadian guideline calculators
Tools developed in Canada, and calculators built on Canadian guidelines.
Developed in Canada
- Canadian CT Head RuleIdentifies which adults with minor head injury (GCS 13–15) need a CT head.
- Canadian C-Spine RuleDetermines which alert, stable adults with blunt trauma need cervical spine imaging.
- Ottawa Knee RuleIdentifies which adults with acute knee injury need knee radiography.
- Ottawa ankle and foot rulesIdentifies which adults with acute ankle injury need ankle and/or foot radiographs.
- Ottawa Subarachnoid Hemorrhage RuleRules out subarachnoid hemorrhage in alert patients with acute non-traumatic headache peaking within 1 hour.
- Ottawa COPD Risk Scale (emergency department)Risk of short-term serious outcomes in emergency department patients with an acute COPD exacerbation, to support disposition decisions.
- Canadian Syncope Risk Score30-day risk of serious adverse events after ED assessment of syncope when no serious cause was found.
- Canadian TIA Score7-day risk of stroke or carotid revascularisation after TIA or minor stroke diagnosed in the ED.
- HERDOO2 rule (stopping anticoagulation after unprovoked VTE in women)Identifies women with a first unprovoked major VTE who are at low risk of recurrence and may stop anticoagulants after the initial treatment period. Not applicable to men.
- Ottawa score (recurrent cancer-associated VTE)Risk of recurrent VTE during the first 6 months of anticoagulation in patients with cancer-associated VTE.
- CATCH2 rule (CT in children with minor head injury)Canadian 8-item rule for head CT in children 0–16 years with minor head injury (GCS 13–15 within 24 h of blunt trauma) and a qualifying feature.
- PRAM (Pediatric Respiratory Assessment Measure)Grades acute asthma severity in children aged 2–17 years (12-point score) at triage and after bronchodilator treatment.
- McIsaac (modified Centor) sore-throat scoreProbability of group A streptococcal pharyngitis in patients ≥3 years with sore throat; decides who needs a throat swab or antibiotics (Canadian-derived).
- Brock University (PanCan) lung nodule malignancy modelProbability that a lung nodule seen on CT is cancer (full model with spiculation, PanCan / Brock University, Canada).
- Familial hypercholesterolemia: simplified Canadian definitionClinical diagnosis of heterozygous familial hypercholesterolemia (definite or probable) using the Canadian (CCS-endorsed) definition.
- Kidney Failure Risk Equation (KFRE, 4- or 8-variable)2- and 5-year risk of kidney failure (dialysis or transplant) in adults with CKD G3–G5; 8-variable version when albumin, phosphate, bicarbonate and calcium are entered.
- Clinical Frailty Scale (CFS 2.0)Grades baseline fitness and frailty in older adults (Rockwood, Dalhousie). Choose the level that best fits the usual state about 2 weeks before the acute illness.
- Toronto HCC Risk Index (THRI)10-year risk of hepatocellular carcinoma in adults with cirrhosis of any cause, from age, sex, etiology and platelets (Toronto derivation, Rotterdam validation).
- miniPIERS (hypertensive disorders of pregnancy)Predicted risk of an adverse maternal outcome within 48 hours of admission in a hypertensive disorder of pregnancy, from clinical signs and symptoms only (no laboratory tests).
- Edmonton Obesity Staging System (EOSS)Clinical and functional staging (0–4) of obesity by its medical, mental and functional impact, to guide treatment intensity alongside BMI.
- CANRISK (Canadian Diabetes Risk Questionnaire)Risk of prediabetes or undiagnosed type 2 diabetes in adults 40 years and older, from questionnaire items (paper-based CANRISK score, 0–86).
- Wells score for pulmonary embolismClinical pretest probability of pulmonary embolism, used with D-dimer to decide on imaging.
- Wells score for deep vein thrombosisClinical pretest probability of lower-limb DVT, used with D-dimer and ultrasound.
- ASPECTS (Alberta Stroke Program Early CT Score)Quantifies early ischemic change in the middle cerebral artery territory on non-contrast CT (10 = normal, 0 = diffuse involvement); used to estimate ischemic core when selecting patients for thrombectomy.
- CIWA-Ar (alcohol withdrawal severity)Clinical Institute Withdrawal Assessment for Alcohol, revised: 10-item clinician rating of alcohol withdrawal severity, used to guide symptom-triggered treatment and monitoring.
- Perianal Crohn’s Disease Activity Index (PDAI)Activity of perianal Crohn’s disease from five items scored 0–4 (total 0–20); PDAI >4 indicates active perianal disease.
- Montreal classification (Crohn’s disease and ulcerative colitis)Phenotype code for adult IBD: Crohn’s age/location/behavior (A, L, B, p) or UC extent and severity (E, S).
Based on Canadian guidelines
- Gestational diabetes diagnosis (Diabetes Canada / SOGC)Applies the Diabetes Canada 2018 and SOGC No. 393 thresholds at 24–28 weeks: preferred two-step (50-g GCT, then 75-g OGTT) or alternative one-step 75-g OGTT.
- Tuberculin skin test interpretation (Canadian TB Standards 2022)Interprets TST induration against the cut-off for the person’s risk group, per Table 1 of Chapter 4 of the Canadian Tuberculosis Standards, 8th edition.
- Modified Bishop score (SOGC 2023)Pre-induction cervical assessment with the SOGC modified Bishop score (cervical length replaces effacement; each item 0–2, maximum 10).
- CCS algorithm (CHADS-65) for AF stroke preventionCanadian Cardiovascular Society 2020 algorithm for choosing antithrombotic therapy in nonvalvular atrial fibrillation or flutter.
- Framingham Risk Score (CCS 2021, general CVD)10-year risk of a first cardiovascular event, with the CCS modification for family history and CCS 2021 statin thresholds.
- CRC screening by family history (CAG 2018)Canadian Association of Gastroenterology Banff consensus: when and how to screen people with a family history of non-hereditary colorectal cancer or adenoma.
- Intrahepatic cholestasis of pregnancy — bile acid bands (SOGC 2024)Diagnosis and birth-timing bands for intrahepatic cholestasis of pregnancy from the peak non-fasting total bile acid level.
- Chronic hepatitis B: treatment eligibility (CASL/AMMI 2025 vs AASLD-IDSA 2025)Applies the 2025 Canadian (CASL/AMMI) and US (AASLD-IDSA) treatment criteria to an HBsAg-positive adult and shows where they differ.