Emergency · LIVE

PEG (Krebs)

PEG

Compute the Krebs 2009 PEG as the unweighted mean of three caller-assigned 0-10 integers (pain_average, enjoyment_of_life, general_activity). Potential range 0-10. Krebs 2009 did not publish a diagnostic cutoff.

LIVE $0.005 USDC GET /api/calc/peg

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

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

What it computes

Compute the Krebs 2009 PEG as the unweighted mean of three caller-assigned 0-10 integers (pain_average, enjoyment_of_life, general_activity). Potential range 0-10. Krebs 2009 did not publish a diagnostic cutoff.

When to use

When an agent has already assigned Krebs 2009 PEG integers 0-10 for average pain, enjoyment-of-life interference, and general-activity interference in the past week and needs the published mean, not a pain diagnosis, opioid order, Brief Pain Inventory total, or an invented severity band.

When not to use

• Not a medical device and not a pain diagnosis or opioid order.
• Each item is a caller-assigned integer 0-10. magent does not interview the patient.
• Krebs 2009 did not publish a diagnostic cutoff. magent does not invent mild, moderate, or severe bands.
• This is the three-item PEG mean, not the full Brief Pain Inventory.

Formula

PEG = (pain_average + enjoyment_of_life + general_activity) / 3; each caller-assigned 0-10; Krebs 2009; potential range 0-10

Citation

Title

Development and initial validation of the PEG, a three-item scale assessing pain intensity and interference

Authors

Krebs EE, Lorenz KA, Bair MJ, Damush TM, Wu J, Sutherland JM, Asch SM, Kroenke K

Source

J Gen Intern Med. 2009;24(6):733-738

DOI

10.1007/s11606-009-0981-1

Worked example

Also searched as

• PEG
• PEG scale
• Pain Enjoyment General activity
• Krebs PEG
• Krebs 2009 PEG
• three-item PEG
• pain interference scale
• PEG score

Try

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

/api/calc/peg?pain_average=0&enjoyment_of_life=0&general_activity=0

Full URL: https://api.magentlab.com/api/calc/peg?pain_average=0&enjoyment_of_life=0&general_activity=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/peg?pain_average=0&enjoyment_of_life=0&general_activity=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/peg 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": [
    {
      "enjoyment_of_life": "0",
      "general_activity": "0",
      "pain_average": "0"
    },
    {
      "enjoyment_of_life": "0",
      "general_activity": "0",
      "pain_average": "0"
    }
  ]
}

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/peg",
  "items": [
    {
      "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": "Krebs EE, Lorenz KA, Bair MJ, Damush TM, Wu J, Sutherland JM, Asch SM, Kroenke K",
        "doi": "10.1007/s11606-009-0981-1",
        "id": "krebs-2009",
        "pmid": "19418100",
        "source": "J Gen Intern Med. 2009;24(6):733-738",
        "title": "Development and initial validation of the PEG, a three-item scale assessing pain intensity and interference"
      },
      "formula": "peg",
      "formula_expression": "PEG = (pain_average + enjoyment_of_life + general_activity) / 3; each caller-assigned 0-10; Krebs 2009; potential range 0-10",
      "max_score": 10,
      "score": 0.0,
      "enjoyment_of_life": 0,
      "general_activity": 0,
      "pain_average": 0
    },
    {
      "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": "Krebs EE, Lorenz KA, Bair MJ, Damush TM, Wu J, Sutherland JM, Asch SM, Kroenke K",
        "doi": "10.1007/s11606-009-0981-1",
        "id": "krebs-2009",
        "pmid": "19418100",
        "source": "J Gen Intern Med. 2009;24(6):733-738",
        "title": "Development and initial validation of the PEG, a three-item scale assessing pain intensity and interference"
      },
      "formula": "peg",
      "formula_expression": "PEG = (pain_average + enjoyment_of_life + general_activity) / 3; each caller-assigned 0-10; Krebs 2009; potential range 0-10",
      "max_score": 10,
      "score": 0.0,
      "enjoyment_of_life": 0,
      "general_activity": 0,
      "pain_average": 0
    }
  ]
}

Response

Example JSON

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

{
  "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": "Krebs EE, Lorenz KA, Bair MJ, Damush TM, Wu J, Sutherland JM, Asch SM, Kroenke K",
    "doi": "10.1007/s11606-009-0981-1",
    "id": "krebs-2009",
    "pmid": "19418100",
    "source": "J Gen Intern Med. 2009;24(6):733-738",
    "title": "Development and initial validation of the PEG, a three-item scale assessing pain intensity and interference"
  },
  "formula": "peg",
  "formula_expression": "PEG = (pain_average + enjoyment_of_life + general_activity) / 3; each caller-assigned 0-10; Krebs 2009; potential range 0-10",
  "max_score": 10,
  "score": 0.0,
  "enjoyment_of_life": 0,
  "general_activity": 0,
  "pain_average": 0
}

Client errors (HTTP 400)

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

Related tools

• PAINAD — Sum five caller-assigned Warden 2003 PAINAD integers (0-2) and return the published total (max 10).
• FLACC — Sum five caller-assigned Merkel 1997 FLACC integers (0-2) and return the published total (max 10).
• CPOT — Sum four caller-assigned Gélinas 2006 CPOT integers (0-2) and return the published total (max 8). The fourth item is ventilator_compliance when intubated or vocalization when extubated.
• BPS — Sum three caller-assigned Payen 2001 BPS integers (1-4) and return the published total (range 3-12).

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.