You're in clinic and a patient needs admission. Do they go directly to the floor or through the ED? It sounds simple, but getting it wrong matters. Send someone to the floor who needed the ED, and you miss a window for stabilization. Send a stable patient through the ED unnecessarily, and you've just added hours to their day and clogged an already busy department.

The problem

This decision usually comes down to gut feeling and experience. Seasoned attendings develop the instinct over time, but residents and newer clinicians don't have that yet. And even experienced physicians aren't always consistent about it.

What I built

I built an Ambulatory Triage Calculator that standardizes this decision using validated clinical scoring systems. It pulls from three established tools:

• HOSPITAL Score (C-statistic 0.72, n=117,065) - predicts 30-day readmission risk
• National Early Warning Score 2 (NEWS2) (AUROC 0.86 for mortality) - identifies patients at risk of deterioration
• Glasgow Admission Prediction Score (AUROC 0.741) - predicts need for hospital admission

How It Works

The calculator evaluates patients across three key domains:

1. Vital Signs & Clinical Presentation (0-7 points)

• Temperature >38.5°C (101.3°F): +1 point
• Heart Rate 100-119 bpm: +1 point
• Respiratory Rate 20-23/min: +1 point
• Systolic BP 90-100 mmHg: +2 points
• O₂ Saturation 90-94%: +2 points

2. Patient Risk Factors (0-5 points)

• Age ≥75 years: +1 point
• ≥3 Active Medical Problems: +1 point
• Hospitalization within 30 days: +2 points
• Limited Home Support/Lives Alone: +1 point

3. Clinical Concern Factors (0-5 points)

• Unclear Diagnosis Requiring Workup: +2 points
• Likely Needs Specialist Consultation: +1 point
• Significant Lab Abnormalities: +1 point
• Urgent Imaging Required: +1 point

Risk Stratification

Based on the total score, patients are categorized into three risk levels:

• 0-3 points (Low Risk): Direct Admission recommended
• 4-6 points (Moderate Risk): Direct Admission or ED Transfer (clinical judgment)
• ≥7 points (High Risk): ED Transfer recommended

Using the calculator

{:class="gif"}

Important Safety Features

The calculator includes absolute contraindications that mandate immediate ED transfer regardless of score:

• Hemodynamic instability
• Respiratory distress (O₂ sat <90%, RR >24/min with distress)
• Altered mental status or acute neurological symptoms
• Chest pain with abnormal EKG or suspected acute coronary syndrome
• Active bleeding or severe pain

Building the app

The Ambulatory Triage Calculator is built with vanilla HTML, CSS, and JavaScript. No framework needed. The calculator does basic math and doesn't need state management or API calls, so keeping it simple made sense. It loads fast, works offline once cached, and runs on any device with a browser.

I deployed it on Surge.sh because the workflow is dead simple: run surge from the command line and you're live. HTTPS by default, good uptime, free tier covers everything. For a clinical tool that needs to be reliably available, it works well.

Why it helps

The calculator does a few things: it makes the decision consistent regardless of who's using it, it reduces the mental overhead on a busy clinic day, and it creates a record of the clinical reasoning behind the triage choice. For residents, it's a structured way to think through a decision that otherwise relies on pattern recognition they haven't built up yet.

Wrapping up

This isn't meant to replace clinical judgment. It's a tool to support it. The scoring system gives you a framework, but you still have to use your brain. If something feels off about a patient, trust that instinct regardless of what the score says.

---

References

1. Donzé J, Aujesky D, Williams D, Schnipper JL. Potentially Avoidable 30-Day Hospital Readmissions in Medical Patients: Derivation and Validation of a Prediction Model. JAMA Internal Medicine. 2013;173(8):632-638.

2. Smith GB, Prytherch DR, Meredith P, Schmidt PE, Featherstone PI. The ability of the National Early Warning Score (NEWS) to discriminate patients at risk of early cardiac arrest, unanticipated intensive care unit admission, and death. Resuscitation. 2013;84(4):465-470.

3. Cameron A, Rodgers K, Ireland A, Jamdar R, McKay GA. A simple tool to predict admission at the time of triage. Emergency Medicine Journal. 2015;32(3):174-179.

4. Lewis G, Kirkham H, Duncan I, Vaithianathan R. How health systems could avert 'triple fail' events that are harmful, costly, and ineffective. Health Affairs. 2013;32(4):669-676.

5. Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003;58(5):377-382.

6. Subbe CP, Kruger M, Rutherford P, Gemmel L. Validation of a modified Early Warning Score in medical admissions. QJM. 2001;94(10):521-526.

7. Howell E, Bessman E, Marshall R, Wright S. Hospitalist bed management effecting throughput from the emergency department to the intensive care unit. Journal of Critical Care. 2010;25(2):184-189.