RCRI calculator
The Revised Cardiac Risk Index, often called Lee's index after the 1999 Circulation derivation, is a six-item preoperative score for major cardiac complications after noncardiac surgery.
Run — free
Runs in your browser. Free, unlimited — your data never leaves this page.
This calculator accepts six clinical flags—high-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, and a creatinine above 2.0 mg/dL—and returns the integer score from zero through six, risk class I through IV, and the published Lee major-cardiac-event percentage. Every factor must be a JSON boolean or a 0/1 value; a missing field or any other token fails with invalid_input and is not billed. The same deterministic module powers the free browser widget and the API path, so teaching keys, research coding, and product prototypes never disagree on a given vignette. Treat the JSON as a transparent arithmetic aid, not a diagnosis or a substitute for licensed clinical judgment about anesthesia, monitoring, or whether to proceed with an operation.
How to use it
Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.
Check your inputs
Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.
Use it again or automate it
Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.
What you can do with it
Get an answer now
Enter one set of values and see the result without building a spreadsheet or script.
Compare scenarios
Change one value at a time and rerun the calculation to understand what affects the result.
Automate repeated work
Use the API when the same calculation needs to run inside your product or workflow.
FAQ
What is the Revised Cardiac Risk Index (RCRI)?
It is Lee's 1999 six-item preoperative score for major cardiac complications after noncardiac surgery. This tool returns the integer score (0–6), risk class I–IV, a short label, and the published major-cardiac-event percentage.
Which six factors does the calculator count?
High-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, and preoperative creatinine greater than 2.0 mg/dL. Each present factor adds one point.
What happens if a factor is not a boolean or 0/1?
The call fails with invalid_input naming the field. Every factor must be a JSON boolean or a 0/1 value; missing fields and tokens such as yes are rejected and are not billed.
How should I interpret risk classes I through IV?
Class I (0 points) is low risk at 0.4%. Class II (1 point) is low-intermediate at 0.9%. Class III (2 points) is intermediate at 6.6%. Class IV (≥3 points) is high risk at 11%. Figures are historical cohort rates, not a personal prognosis.
Can I use this result to clear a patient for surgery?
No. This is an educational arithmetic aid, not medical advice. Cardiac clearance, monitoring, and whether to proceed need a licensed clinician and the rest of the clinical picture this calculator does not collect.
What does the RCRI calculator cost?
The browser widget runs free and locally. The same computation via the API is billed at $0.002 per successful request from prepaid KIT balance; invalid_input failures are not charged.
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/health/rcri \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"items":["valor-1","valor-2"]}'const res = await fetch("https://api.kit.forhosting.com/health/rcri", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"items": [
"valor-1",
"valor-2"
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/rcri",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"items": [
"valor-1",
"valor-2"
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/rcri", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"items":["valor-1","valor-2"]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"items":["valor-1","valor-2"]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/rcri", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"items": [
"valor-1",
"valor-2"
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.rcri",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |