Calc Sf Ratio
by magent in Other
SpO2/FiO2 (S/F) ratio as pulse-oximetry SpO2 percent divided by inspired oxygen as a fraction (0.21–1.0) (Rice 2007). Returns the ratio rounded to one decimal. Magent does not apply ARDS or Berlin bands. This is not the PaO2/FiO2 (P/F) ratio and not the ROX index.
https://api.magentlab.com/api/calc/sf_ratio- Price
- $0.007
- per call in USDC
- Uptime
- 100%
- last 30 days
- Response time
- 146 ms
- 572 ms slowest 5%
- Last check
- Passed
- 4 h ago, next any minute now
Reliability
Status and outage history · Atom feed · Watch with other listings
How to call it
POST https://api.magentlab.com/api/calc/sf_ratio
Each call costs $0.007 in USDC on Base, paid with the request over x402.
Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.
Example request
From the listing.
POST https://api.magentlab.com/api/calc/sf_ratio
content-type: application/json
{
"items": [
{
"fio2": 0.21,
"spo2_percent": 95
},
{
"fio2": 0.21,
"spo2_percent": 95
}
]
}Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
items | array of object | Yes |
Example response
The provider's example. We can't check it without paying.
Example response, 36 lines
{
"count": 2,
"items": [
{
"citation": {
"authors": "Rice TW, Wheeler AP, Bernard GR, Hayden DL, Schoenfeld DA, Ware LB",
"doi": "10.1378/chest.07-0617",
"id": "rice-2007",
"source": "Chest. 2007;132(2):410-417",
"title": "Comparison of the SpO2/FIO2 ratio and the PaO2/FIO2 ratio in patients with acute lung injury or ARDS"
},
"disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
"fio2": 0.21,
"formula": "sf_ratio",
"formula_expression": "sf_ratio = spo2_percent / fio2",
"sf_ratio": 452.4,
"spo2_percent": 95
},
{
"citation": {
"authors": "Rice TW, Wheeler AP, Bernard GR, Hayden DL, Schoenfeld DA, Ware LB",
"doi": "10.1378/chest.07-0617",
"id": "rice-2007",
"source": "Chest. 2007;132(2):410-417",
"title": "Comparison of the SpO2/FIO2 ratio and the PaO2/FIO2 ratio in patients with acute lung injury or ARDS"
},
"disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
"fio2": 0.21,
"formula": "sf_ratio",
"formula_expression": "sf_ratio = spo2_percent / fio2",
"sf_ratio": 452.4,
"spo2_percent": 95
}
],
"path": "/api/calc/sf_ratio"
}Call it from code
The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.007.
curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.magentlab.com/api/calc/sf_ratio' \
-H 'content-type: application/json' \
--data-raw '{"items":[{"fio2":0.21,"spo2_percent":95},{"fio2":0.21,"spo2_percent":95}]}'
# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://api.magentlab.com/api/calc/sf_ratio' \
-H 'content-type: application/json' \
--data-raw '{"items":[{"fio2":0.21,"spo2_percent":95},{"fio2":0.21,"spo2_percent":95}]}' \
| grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decodeJavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
// Pays at most $0.007 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.007" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);
// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.007 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.magentlab.com%2Fapi%2Fcalc%2Fsf_ratio&method=POST
const res = await pay("https://api.magentlab.com/api/calc/sf_ratio", {
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({
"items": [
{
"fio2": 0.21,
"spo2_percent": 95
},
{
"fio2": 0.21,
"spo2_percent": 95
}
]
}),
});
console.log(res.status, await res.text());Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client
# Pays at most $0.007 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.007"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))
with x402_requests(client) as session:
res = session.post(
"https://api.magentlab.com/api/calc/sf_ratio",
json={
"items": [
{
"fio2": 0.21,
"spo2_percent": 95,
},
{
"fio2": 0.21,
"spo2_percent": 95,
},
],
},
)
print(res.status_code, res.text)Security scan
1 finding
- Charges more than its listed price in payment
Listed at $0.005, charges $0.007
Recent checks
| When | Result | HTTP | Time | Price |
|---|---|---|---|---|
| 4 h ago | Passed | 402 | 171 ms | $0.007 |
| 9 h ago | Passed | 402 | 143 ms | $0.007 |
| 14 h ago | Passed | 402 | 280 ms | $0.007 |
| 18 h ago | Passed | 402 | 145 ms | $0.007 |
| 23 h ago | Passed | 402 | 141 ms | $0.007 |
Show 10 older checks
| 27 h ago | Passed | 402 | 145 ms | $0.007 |
| 31 h ago | Passed | 402 | 139 ms | $0.007 |
| 35 h ago | Passed | 402 | 133 ms | $0.007 |
| 39 h ago | Passed | 402 | 572 ms | $0.007 |
| 44 h ago | Passed | 402 | 146 ms | $0.007 |
| 2 days ago | Passed | 402 | 238 ms | $0.007 |
| 2 days ago | Passed | 402 | 217 ms | $0.007 |
| 2 days ago | Passed | 402 | 250 ms | $0.007 |
| 3 days ago | Passed | 402 | 140 ms | $0.007 |
| 3 days ago | Passed | 402 | 144 ms | $0.007 |
History
| 11 Oct 2026 | Price changed from $0.005 to $0.007 |