Respiratory · LIVE

qCSI (quick COVID-19 Severity Index)

qCSI

Sum Haimovich 2020 qCSI bedside points (Table 2) from respiratory rate, lowest SpO2, and nasal-cannula oxygen flow and return the integer total (max 12).

LIVE $0.005 USDC GET /api/calc/qcsi

Markdown: /docs/qcsi.md · Canonical: https://magentlab.com/docs/qcsi

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Sum Haimovich 2020 qCSI bedside points (Table 2) from respiratory rate, lowest SpO2, and nasal-cannula oxygen flow and return the integer total (max 12).

When to use

When an agent needs the published qCSI bedside point total and must not invent risk classes, treat the score as a COVID-19 diagnosis or triage order, or substitute the 12-variable CSI model.

When not to use

• Not a medical device and not a COVID-19 diagnosis or triage order. magent does not measure vitals.
• This is the Haimovich 2020 qCSI bedside points score (Table 2; max 12) only. It is not the 12-variable gradient-boosting CSI model.
• Derivation included nasal cannula oxygen ≤6 L/min and excluded higher flows. oxygen_l_min >6 is rejected.
• Respiratory rate, SpO2, and oxygen flow are caller-supplied. magent does not measure them. The paper associated a low score with <5% decompensation; magent returns the integer total only and does not emit named risk classes.

Formula

qCSI = RR(≤22→0, 23–28→1, >28→2) + SpO2(>92→0, 89–92→2, ≤88→5) + O2_L_min(≤2→0, 3–4→4, 5–6→5); Haimovich 2020 Table 2 bedside; max 12

Citation

Title

Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation

Authors

Haimovich AD, Ravindra NG, Stoytchev S, Young HP, Wilson FP, van Dijk D, Schulz WL, Taylor RA

Source

Ann Emerg Med. 2020;76(4):442-453

DOI

10.1016/j.annemergmed.2020.07.022

Worked example

Also searched as

• qCSI
• quick COVID-19 Severity Index
• Haimovich qCSI
• qCSI score
• quick CSI
• COVID-19 severity index
• Haimovich 2020 qCSI
• bedside qCSI

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/qcsi?respiratory_rate=16&spo2_percent=98&oxygen_l_min=0

Full URL: https://api.magentlab.com/api/calc/qcsi?respiratory_rate=16&spo2_percent=98&oxygen_l_min=0

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/qcsi?respiratory_rate=16&spo2_percent=98&oxygen_l_min=0"

Parameters

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/qcsi Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

• 1 to 25 items. Each item uses the same keys as the GET query parameters.
• POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
• The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
• HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
• Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
• x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "oxygen_l_min": "0",
      "respiratory_rate": "16",
      "spo2_percent": "98"
    },
    {
      "oxygen_l_min": "0",
      "respiratory_rate": "16",
      "spo2_percent": "98"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/qcsi",
  "items": [
    {
      "components": [
        {
          "value": 16,
          "factor": "respiratory_rate",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "value": 0.0,
          "factor": "oxygen_l_min",
          "points": 0,
          "present": false
        }
      ],
      "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.",
      "citation": {
        "authors": "Haimovich AD, Ravindra NG, Stoytchev S, Young HP, Wilson FP, van Dijk D, Schulz WL, Taylor RA",
        "doi": "10.1016/j.annemergmed.2020.07.022",
        "id": "haimovich-2020",
        "pmid": "33012378",
        "source": "Ann Emerg Med. 2020;76(4):442-453",
        "title": "Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation"
      },
      "formula": "qcsi",
      "formula_expression": "qCSI = RR(≤22→0, 23–28→1, >28→2) + SpO2(>92→0, 89–92→2, ≤88→5) + O2_L_min(≤2→0, 3–4→4, 5–6→5); Haimovich 2020 Table 2 bedside; max 12",
      "max_score": 12,
      "score": 0,
      "spo2_percent": 98.0,
      "respiratory_rate": 16,
      "oxygen_l_min": 0.0
    },
    {
      "components": [
        {
          "value": 16,
          "factor": "respiratory_rate",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "value": 0.0,
          "factor": "oxygen_l_min",
          "points": 0,
          "present": false
        }
      ],
      "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.",
      "citation": {
        "authors": "Haimovich AD, Ravindra NG, Stoytchev S, Young HP, Wilson FP, van Dijk D, Schulz WL, Taylor RA",
        "doi": "10.1016/j.annemergmed.2020.07.022",
        "id": "haimovich-2020",
        "pmid": "33012378",
        "source": "Ann Emerg Med. 2020;76(4):442-453",
        "title": "Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation"
      },
      "formula": "qcsi",
      "formula_expression": "qCSI = RR(≤22→0, 23–28→1, >28→2) + SpO2(>92→0, 89–92→2, ≤88→5) + O2_L_min(≤2→0, 3–4→4, 5–6→5); Haimovich 2020 Table 2 bedside; max 12",
      "max_score": 12,
      "score": 0,
      "spo2_percent": 98.0,
      "respiratory_rate": 16,
      "oxygen_l_min": 0.0
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "components": [
    {
      "value": 16,
      "factor": "respiratory_rate",
      "points": 0,
      "present": false
    },
    {
      "value": 98.0,
      "factor": "spo2_percent",
      "points": 0,
      "present": false
    },
    {
      "value": 0.0,
      "factor": "oxygen_l_min",
      "points": 0,
      "present": false
    }
  ],
  "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.",
  "citation": {
    "authors": "Haimovich AD, Ravindra NG, Stoytchev S, Young HP, Wilson FP, van Dijk D, Schulz WL, Taylor RA",
    "doi": "10.1016/j.annemergmed.2020.07.022",
    "id": "haimovich-2020",
    "pmid": "33012378",
    "source": "Ann Emerg Med. 2020;76(4):442-453",
    "title": "Development and Validation of the Quick COVID-19 Severity Index: A Prognostic Tool for Early Clinical Decompensation"
  },
  "formula": "qcsi",
  "formula_expression": "qCSI = RR(≤22→0, 23–28→1, >28→2) + SpO2(>92→0, 89–92→2, ≤88→5) + O2_L_min(≤2→0, 3–4→4, 5–6→5); Haimovich 2020 Table 2 bedside; max 12",
  "max_score": 12,
  "score": 0,
  "spo2_percent": 98.0,
  "respiratory_rate": 16,
  "oxygen_l_min": 0.0
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• HACOR — Sum Duan 2017 HACOR (ESM Table 2) points from heart rate, pH, GCS, PaO2/FiO2, and respiratory rate and return low (≤5) or high (>5).

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

• HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged.
• exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
• HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
• Execution is timeout-bounded and concurrency-capped.
• Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.