# PRIEST COVID-19 clinical severity (Goodacre)

PRIEST

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/priest`
HTML: https://magentlab.com/docs/priest
Markdown: https://magentlab.com/docs/priest.md

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

## What it computes

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.

## When to use

When an agent already has NEWS2 Scale 1 vitals, age, sex, and performance and needs the published Goodacre 2021 PRIEST total and the ≤4 low adverse-outcome flag, not NEWS2, 4C, or an admission order.

## When not to use

- Not a medical device and not an admission, discharge, or treatment order. magent does not measure vitals or examine the patient.
- SpO2 uses NEWS2 Chart 1 Scale 1 only. magent does not implement NEWS2 SpO2 Scale 2 (prescribed 88-92% target in hypercapnic respiratory failure).
- This is not NEWS2 and not the ISARIC 4C Mortality Score. Alertness is caller-assigned alert (0) or confused_or_not_alert (3); it is not full ACVPU and not GCS.
- Age is 16-120 years as published for PRIEST adults. Age 80 scores 3; age >80 scores 4.
- low_adverse_outcome_risk is true only when the total is ≤4 (Goodacre 2021: scores of four or less). magent does not invent named high-risk groups or mortality percents.

## Formula

```
PRIEST = rr_points + spo2_scale1_points + oxygen_points + temp_points + sbp_points + hr_points + alertness_points + sex_points + age_points + performance_points; NEWS2 Chart 1 Scale 1 vitals (not Scale 2) + age + sex + performance; Goodacre 2021 Fig 2; max 29; low_adverse_outcome_risk iff score ≤4
```

## Citation

[Derivation and validation of a clinical severity score for acutely ill adults with suspected COVID-19: The PRIEST observational cohort study](https://doi.org/10.1371/journal.pone.0245840)
Goodacre S, Thomas B, Sutton L, et al.
PLoS One. 2021;16(1):e0245840
DOI: [10.1371/journal.pone.0245840](https://doi.org/10.1371/journal.pone.0245840)

## Worked example

### Age 70 male, otherwise zero-point vitals (score 4)

Given: `age_years=70, alertness=alert, heart_rate_bpm=70, performance_status=unrestricted, respiratory_rate=16, sex=male, spo2_percent=98, supplemental_oxygen=false, systolic_mm_hg=120, temperature_c=37.0`

1. RR 16 → 0; Scale 1 SpO2 98 → 0; oxygen false → 0; temperature 37.0 → 0; SBP 120 → 0; HR 70 → 0; alertness alert → 0; unrestricted → 0
2. Age 70 → 3; male → 1
3. Score = 4 (max 29); low_adverse_outcome_risk = true


### Age 81 male, otherwise zero-point vitals (score 5)

Given: `age_years=81, alertness=alert, heart_rate_bpm=70, performance_status=unrestricted, respiratory_rate=16, sex=male, spo2_percent=98, supplemental_oxygen=false, systolic_mm_hg=120, temperature_c=37.0`

1. Age 81 → 4; male → 1; remaining parameters → 0
2. Score = 5 (max 29); low_adverse_outcome_risk = false


## Also searched as

- PRIEST score
- PRIEST COVID-19
- Pandemic Respiratory Infection Emergency System Triage
- Goodacre PRIEST
- COVID-19 clinical severity score
- PRIEST observational cohort
- NEWS2 plus age sex performance

## Parameters

- `age_years` (integer, required): Age in years (integer 16-120). Goodacre 2021 PRIEST: 16-49 → 0; 50-65 → 2; 66-80 → 3; >80 → 4. Age 80 scores 3; age 81 scores 4.
- `sex` (string, required): Sex (female or male). Goodacre 2021 PRIEST: female → 0; male → 1.
- `respiratory_rate` (integer, required): Respiratory rate in breaths/min (integer 0-80). NEWS2 Chart 1 Scale 1 as used in PRIEST: 12-20 → 0; 9-11 → 1; 21-24 → 2; <9 or >24 → 3.
- `spo2_percent` (number, required): Oxygen saturation percent (50-100). NEWS2 Chart 1 Scale 1 only: >95 → 0; 94-95 → 1; 92-93 → 2; <92 → 3. magent does not implement NEWS2 SpO2 Scale 2.
- `heart_rate_bpm` (integer, required): Heart rate in beats/min (integer 30-220). NEWS2 Chart 1: 51-90 → 0; 41-50 or 91-110 → 1; 111-130 → 2; <41 or >130 → 3.
- `systolic_mm_hg` (integer, required): Systolic blood pressure in mm Hg (integer 0-300). NEWS2 Chart 1: 111-219 → 0; 101-110 → 1; 91-100 → 2; <91 or >219 → 3.
- `temperature_c` (number, required): Temperature in °C (30.0-45.0). NEWS2 Chart 1: 36.1-38.0 → 0; 35.1-36.0 or 38.1-39.0 → 1; >39.0 → 2; <35.1 → 3. magent does not convert Fahrenheit.
- `alertness` (string, required): Caller-assigned alertness (alert or confused_or_not_alert). Goodacre 2021 PRIEST: alert → 0; confused_or_not_alert → 3. Not full ACVPU and not GCS.
- `supplemental_oxygen` (boolean, required): Any supplemental oxygen as assigned by the caller (true or false). NEWS2 Chart 1 inspired oxygen: air/false → 0; supplemental/true → 2.
- `performance_status` (string, required): Caller-assigned performance (unrestricted, limited_strenuous, limited_activity, limited_self_care, or bed_chair_bound). Goodacre 2021: unrestricted → 0; limited strenuous activity, can do light activity → 1; limited activity, can self-care → 2; limited self-care → 3; bed/chair bound, no self-care → 4.

## 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.

Method: `POST /api/calc/priest`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: 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:

```json
{
  "items": [
    {
      "age_years": "70",
      "alertness": "alert",
      "heart_rate_bpm": "70",
      "performance_status": "unrestricted",
      "respiratory_rate": "16",
      "sex": "male",
      "spo2_percent": "98",
      "supplemental_oxygen": "false",
      "systolic_mm_hg": "120",
      "temperature_c": "37.0"
    },
    {
      "age_years": "70",
      "alertness": "alert",
      "heart_rate_bpm": "70",
      "performance_status": "unrestricted",
      "respiratory_rate": "16",
      "sex": "male",
      "spo2_percent": "98",
      "supplemental_oxygen": "false",
      "systolic_mm_hg": "120",
      "temperature_c": "37.0"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/priest

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/priest",
  "items": [
    {
      "components": [
        {
          "value": 70,
          "factor": "age_years",
          "points": 3,
          "present": true
        },
        {
          "value": "male",
          "factor": "sex",
          "points": 1,
          "present": true
        },
        {
          "value": 16,
          "factor": "respiratory_rate",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "value": 70,
          "factor": "heart_rate_bpm",
          "points": 0,
          "present": false
        },
        {
          "value": 120,
          "factor": "systolic_mm_hg",
          "points": 0,
          "present": false
        },
        {
          "value": 37.0,
          "factor": "temperature_c",
          "points": 0,
          "present": false
        },
        {
          "value": "alert",
          "factor": "alertness",
          "points": 0,
          "present": false
        },
        {
          "value": false,
          "factor": "supplemental_oxygen",
          "points": 0,
          "present": false
        },
        {
          "value": "unrestricted",
          "factor": "performance_status",
          "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": "Goodacre S, Thomas B, Sutton L, et al.",
        "doi": "10.1371/journal.pone.0245840",
        "id": "goodacre-2021",
        "pmid": "33481930",
        "source": "PLoS One. 2021;16(1):e0245840",
        "title": "Derivation and validation of a clinical severity score for acutely ill adults with suspected COVID-19: The PRIEST observational cohort study"
      },
      "formula": "priest",
      "formula_expression": "PRIEST = rr_points + spo2_scale1_points + oxygen_points + temp_points + sbp_points + hr_points + alertness_points + sex_points + age_points + performance_points; NEWS2 Chart 1 Scale 1 vitals (not Scale 2) + age + sex + performance; Goodacre 2021 Fig 2; max 29; low_adverse_outcome_risk iff score ≤4",
      "max_score": 29,
      "score": 4,
      "systolic_mm_hg": 120,
      "age_years": 70,
      "sex": "male",
      "heart_rate_bpm": 70,
      "temperature_c": 37.0,
      "spo2_percent": 98.0,
      "respiratory_rate": 16,
      "supplemental_oxygen": false,
      "alertness": "alert",
      "low_adverse_outcome_risk": true,
      "performance_status": "unrestricted"
    },
    {
      "components": [
        {
          "value": 70,
          "factor": "age_years",
          "points": 3,
          "present": true
        },
        {
          "value": "male",
          "factor": "sex",
          "points": 1,
          "present": true
        },
        {
          "value": 16,
          "factor": "respiratory_rate",
          "points": 0,
          "present": false
        },
        {
          "value": 98.0,
          "factor": "spo2_percent",
          "points": 0,
          "present": false
        },
        {
          "value": 70,
          "factor": "heart_rate_bpm",
          "points": 0,
          "present": false
        },
        {
          "value": 120,
          "factor": "systolic_mm_hg",
          "points": 0,
          "present": false
        },
        {
          "value": 37.0,
          "factor": "temperature_c",
          "points": 0,
          "present": false
        },
        {
          "value": "alert",
          "factor": "alertness",
          "points": 0,
          "present": false
        },
        {
          "value": false,
          "factor": "supplemental_oxygen",
          "points": 0,
          "present": false
        },
        {
          "value": "unrestricted",
          "factor": "performance_status",
          "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": "Goodacre S, Thomas B, Sutton L, et al.",
        "doi": "10.1371/journal.pone.0245840",
        "id": "goodacre-2021",
        "pmid": "33481930",
        "source": "PLoS One. 2021;16(1):e0245840",
        "title": "Derivation and validation of a clinical severity score for acutely ill adults with suspected COVID-19: The PRIEST observational cohort study"
      },
      "formula": "priest",
      "formula_expression": "PRIEST = rr_points + spo2_scale1_points + oxygen_points + temp_points + sbp_points + hr_points + alertness_points + sex_points + age_points + performance_points; NEWS2 Chart 1 Scale 1 vitals (not Scale 2) + age + sex + performance; Goodacre 2021 Fig 2; max 29; low_adverse_outcome_risk iff score ≤4",
      "max_score": 29,
      "score": 4,
      "systolic_mm_hg": 120,
      "age_years": 70,
      "sex": "male",
      "heart_rate_bpm": 70,
      "temperature_c": 37.0,
      "spo2_percent": 98.0,
      "respiratory_rate": 16,
      "supplemental_oxygen": false,
      "alertness": "alert",
      "low_adverse_outcome_risk": true,
      "performance_status": "unrestricted"
    }
  ]
}
```

## Response fields

- `formula` (string): priest
- `formula_expression` (string): Exact expression used
- `score` (integer): PRIEST points 0-29
- `max_score` (integer): Always 29
- `low_adverse_outcome_risk` (boolean): true iff score ≤4 (Goodacre 2021: scores of four or less). Not a named high-risk group and not a mortality percent.
- `age_years` (integer): Age used, years
- `sex` (string): Sex used (female or male)
- `respiratory_rate` (integer): Respiratory rate used, breaths/min
- `spo2_percent` (number): SpO2 percent used (Scale 1)
- `heart_rate_bpm` (integer): Heart rate used, bpm
- `systolic_mm_hg` (integer): Systolic BP used, mm Hg
- `temperature_c` (number): Temperature used, °C
- `alertness` (string): Caller-assigned alertness used (alert or confused_or_not_alert)
- `supplemental_oxygen` (boolean): Supplemental oxygen flag used
- `performance_status` (string): Caller-assigned performance status used
- `components` (array): Per-item points
- `citation` (object): Goodacre 2021 PLoS One citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "value": 70,
      "factor": "age_years",
      "points": 3,
      "present": true
    },
    {
      "value": "male",
      "factor": "sex",
      "points": 1,
      "present": true
    },
    {
      "value": 16,
      "factor": "respiratory_rate",
      "points": 0,
      "present": false
    },
    {
      "value": 98.0,
      "factor": "spo2_percent",
      "points": 0,
      "present": false
    },
    {
      "value": 70,
      "factor": "heart_rate_bpm",
      "points": 0,
      "present": false
    },
    {
      "value": 120,
      "factor": "systolic_mm_hg",
      "points": 0,
      "present": false
    },
    {
      "value": 37.0,
      "factor": "temperature_c",
      "points": 0,
      "present": false
    },
    {
      "value": "alert",
      "factor": "alertness",
      "points": 0,
      "present": false
    },
    {
      "value": false,
      "factor": "supplemental_oxygen",
      "points": 0,
      "present": false
    },
    {
      "value": "unrestricted",
      "factor": "performance_status",
      "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": "Goodacre S, Thomas B, Sutton L, et al.",
    "doi": "10.1371/journal.pone.0245840",
    "id": "goodacre-2021",
    "pmid": "33481930",
    "source": "PLoS One. 2021;16(1):e0245840",
    "title": "Derivation and validation of a clinical severity score for acutely ill adults with suspected COVID-19: The PRIEST observational cohort study"
  },
  "formula": "priest",
  "formula_expression": "PRIEST = rr_points + spo2_scale1_points + oxygen_points + temp_points + sbp_points + hr_points + alertness_points + sex_points + age_points + performance_points; NEWS2 Chart 1 Scale 1 vitals (not Scale 2) + age + sex + performance; Goodacre 2021 Fig 2; max 29; low_adverse_outcome_risk iff score ≤4",
  "max_score": 29,
  "score": 4,
  "systolic_mm_hg": 120,
  "age_years": 70,
  "sex": "male",
  "heart_rate_bpm": 70,
  "temperature_c": 37.0,
  "spo2_percent": 98.0,
  "respiratory_rate": 16,
  "supplemental_oxygen": false,
  "alertness": "alert",
  "low_adverse_outcome_risk": true,
  "performance_status": "unrestricted"
}
```

## Errors

- HTTP 400 `invalid_priest_age`: age_years must be an integer from 16 to 120 (Goodacre 2021 PRIEST adults). Returned before settlement; you are not charged.
- HTTP 400 `invalid_priest_performance`: performance_status must be unrestricted, limited_strenuous, limited_activity, limited_self_care, or bed_chair_bound (Goodacre 2021 PRIEST). Returned before settlement; you are not charged.
- HTTP 400 `invalid_priest_alertness`: alertness must be alert or confused_or_not_alert (Goodacre 2021 PRIEST). Returned before settlement; you are not charged.
- HTTP 400 `invalid_sex`: sex must be female or male Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged.
- HTTP 400 `invalid_heart_rate`: heart_rate_bpm must be an integer from 30 to 220 Returned before settlement; you are not charged.
- HTTP 400 `invalid_rts_respiratory_rate`: respiratory_rate must be an integer from 0 to 80. Returned before settlement; you are not charged.
- HTTP 400 `invalid_spo2`: spo2_percent must be a number from 50 to 100. Returned before settlement; you are not charged.
- HTTP 400 `invalid_temperature`: temperature_c must be a number from 30.0 to 45.0. Returned before settlement; you are not charged.
- HTTP 400 `invalid_rts_systolic`: systolic_mm_hg must be an integer from 0 to 300. Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [NEWS2](https://magentlab.com/docs/news2) — Compute the RCP 2017 National Early Warning Score 2 from respiratory rate, SpO2 (Scale 1 or Scale 2), supplemental oxygen, temperature, systolic BP, heart rate, and caller-assigned ACVPU.
- [4C](https://magentlab.com/docs/4c) — Sum the Knight 2020 ISARIC 4C Mortality Score items and return the published Table 5 band (low, intermediate, high, or very high).

## 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.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/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.