Infection / VTE · LIVE

CHOSEN COVID-19 score (Levine)

CHOSEN

Sum the Levine 2020 CHOSEN (COVID Home Safely Now) Figure 2 points from age, oxygen saturation, and serum albumin in g/dL, and return whether the total is at or above the printed cutpoint of 30.

LIVE $0.005 USDC GET /api/calc/chosen

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

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

What it computes

Sum the Levine 2020 CHOSEN (COVID Home Safely Now) Figure 2 points from age, oxygen saturation, and serum albumin in g/dL, and return whether the total is at or above the printed cutpoint of 30.

When to use

When an agent already has adult age, SpO2, and albumin in g/dL and needs the published three-item CHOSEN total (0–55) and the ≥30 cutpoint flag, not a discharge order and not a competing model that adds sex or respiratory rate.

When not to use

• Not a medical device.
• Not a discharge order. magent does not decide disposition, prescribe oxygen, or examine the patient.
• The derivation outcome is a 14-day composite of hypoxia (need for supplemental oxygen), ICU admission, and death in March–April 2020 Mass General Brigham adults with COVID-19. A higher score favored event-free status in that cohort.
• Figure 2 is the three-item model (age, SpO2, albumin g/dL). Sex and respiratory rate are not scored here.
• Cutpoint 30 is the printed derivation threshold (sensitivity 83%, specificity 82%). magent does not convert the total into an individual probability.

Formula

CHOSEN = age_points + spo2_points + albumin_points; Levine 2020 Figure 2; age 18-45 → 5, 46-59 → 2, 60-73 → 1, >73 → 0; SpO2 % <94 → 0, 94-96 → 9, 97-98 → 14, >98 → 21; albumin g/dL <2.8 → 0, 2.8-3.3 → 5, 3.4-3.7 → 15, >3.7 → 29; range 0-55; at_or_above_cutpoint iff score ≥30 (derivation sensitivity 83%, specificity 82%)

Citation

Title

Derivation of a clinical risk score to predict 14-day occurrence of hypoxia, ICU admission, and death among patients with coronavirus disease 2019

Authors

Levine DM, Lipsitz SR, Co Z, Song W, Dykes PC, Samal L

Source

J Gen Intern Med. 2021;36(3):730-737

DOI

10.1007/s11606-020-06353-5

Worked example

Also searched as

• CHOSEN
• COVID Home Safely Now
• Levine CHOSEN
• CHOSEN risk score
• COVID-19 discharge score
• Levine 2020 COVID score
• albumin oxygen saturation age COVID

Try

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

/api/calc/chosen?age=40&spo2_percent=99&albumin_g_dl=4.0

Full URL: https://api.magentlab.com/api/calc/chosen?age=40&spo2_percent=99&albumin_g_dl=4.0

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/chosen?age=40&spo2_percent=99&albumin_g_dl=4.0"

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/chosen 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": [
    {
      "age": "40",
      "albumin_g_dl": "4.0",
      "spo2_percent": "99"
    },
    {
      "age": "40",
      "albumin_g_dl": "4.0",
      "spo2_percent": "99"
    }
  ]
}

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/chosen",
  "items": [
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": 5,
          "present": true
        },
        {
          "value": 99.0,
          "factor": "spo2_percent",
          "points": 21,
          "present": true
        },
        {
          "value": 4.0,
          "factor": "albumin_g_dl",
          "points": 29,
          "present": true
        }
      ],
      "age": 40,
      "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": "Levine DM, Lipsitz SR, Co Z, Song W, Dykes PC, Samal L",
        "doi": "10.1007/s11606-020-06353-5",
        "id": "levine-2020-chosen",
        "pmid": "33274414",
        "source": "J Gen Intern Med. 2021;36(3):730-737",
        "title": "Derivation of a clinical risk score to predict 14-day occurrence of hypoxia, ICU admission, and death among patients with coronavirus disease 2019"
      },
      "formula": "chosen",
      "formula_expression": "CHOSEN = age_points + spo2_points + albumin_points; Levine 2020 Figure 2; age 18-45 → 5, 46-59 → 2, 60-73 → 1, >73 → 0; SpO2 % <94 → 0, 94-96 → 9, 97-98 → 14, >98 → 21; albumin g/dL <2.8 → 0, 2.8-3.3 → 5, 3.4-3.7 → 15, >3.7 → 29; range 0-55; at_or_above_cutpoint iff score ≥30 (derivation sensitivity 83%, specificity 82%)",
      "max_score": 55,
      "score": 55,
      "albumin_g_dl": 4.0,
      "spo2_percent": 99.0,
      "at_or_above_cutpoint": true,
      "cutpoint": 30
    },
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": 5,
          "present": true
        },
        {
          "value": 99.0,
          "factor": "spo2_percent",
          "points": 21,
          "present": true
        },
        {
          "value": 4.0,
          "factor": "albumin_g_dl",
          "points": 29,
          "present": true
        }
      ],
      "age": 40,
      "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": "Levine DM, Lipsitz SR, Co Z, Song W, Dykes PC, Samal L",
        "doi": "10.1007/s11606-020-06353-5",
        "id": "levine-2020-chosen",
        "pmid": "33274414",
        "source": "J Gen Intern Med. 2021;36(3):730-737",
        "title": "Derivation of a clinical risk score to predict 14-day occurrence of hypoxia, ICU admission, and death among patients with coronavirus disease 2019"
      },
      "formula": "chosen",
      "formula_expression": "CHOSEN = age_points + spo2_points + albumin_points; Levine 2020 Figure 2; age 18-45 → 5, 46-59 → 2, 60-73 → 1, >73 → 0; SpO2 % <94 → 0, 94-96 → 9, 97-98 → 14, >98 → 21; albumin g/dL <2.8 → 0, 2.8-3.3 → 5, 3.4-3.7 → 15, >3.7 → 29; range 0-55; at_or_above_cutpoint iff score ≥30 (derivation sensitivity 83%, specificity 82%)",
      "max_score": 55,
      "score": 55,
      "albumin_g_dl": 4.0,
      "spo2_percent": 99.0,
      "at_or_above_cutpoint": true,
      "cutpoint": 30
    }
  ]
}

Response

Example JSON

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

{
  "components": [
    {
      "value": 40,
      "factor": "age",
      "points": 5,
      "present": true
    },
    {
      "value": 99.0,
      "factor": "spo2_percent",
      "points": 21,
      "present": true
    },
    {
      "value": 4.0,
      "factor": "albumin_g_dl",
      "points": 29,
      "present": true
    }
  ],
  "age": 40,
  "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": "Levine DM, Lipsitz SR, Co Z, Song W, Dykes PC, Samal L",
    "doi": "10.1007/s11606-020-06353-5",
    "id": "levine-2020-chosen",
    "pmid": "33274414",
    "source": "J Gen Intern Med. 2021;36(3):730-737",
    "title": "Derivation of a clinical risk score to predict 14-day occurrence of hypoxia, ICU admission, and death among patients with coronavirus disease 2019"
  },
  "formula": "chosen",
  "formula_expression": "CHOSEN = age_points + spo2_points + albumin_points; Levine 2020 Figure 2; age 18-45 → 5, 46-59 → 2, 60-73 → 1, >73 → 0; SpO2 % <94 → 0, 94-96 → 9, 97-98 → 14, >98 → 21; albumin g/dL <2.8 → 0, 2.8-3.3 → 5, 3.4-3.7 → 15, >3.7 → 29; range 0-55; at_or_above_cutpoint iff score ≥30 (derivation sensitivity 83%, specificity 82%)",
  "max_score": 55,
  "score": 55,
  "albumin_g_dl": 4.0,
  "spo2_percent": 99.0,
  "at_or_above_cutpoint": true,
  "cutpoint": 30
}

Client errors (HTTP 400)

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

Related tools

• 4C — Sum the Knight 2020 ISARIC 4C Mortality Score items and return the published Table 5 band (low, intermediate, high, or very high).
• PRIEST — Sum the Goodacre 2021 PRIEST points from NEWS2 Chart 1 Scale 1 vitals, alertness, inspired oxygen, age, sex, and performance status, and return whether the total is ≤4.
• BCRSS — Count the four Duca 2020 BCRSS testing-criteria binaries as assigned by the caller and return the integer total (0–4).

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. HTTP 402 never includes the tool JSON.
• 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.