# EVendo score

EVendo

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

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

## What it computes

Compute the Dong 2019 EVendo score from INR, AST, platelet count, BUN, hemoglobin, and ascites in US conventional units, rounded to 2 decimals, and whether that score is strictly below the published 3.90 cutoff.

## When to use

When an agent already has INR, AST, platelets, BUN, hemoglobin, and an ascites assignment and needs the published Dong 2019 EVendo arithmetic and 3.90 cutoff, not a varices diagnosis, endoscopy order, or invented risk class.

## When not to use

- Not a medical device. Not a varices diagnosis or an endoscopy order. magent does not assay labs.
- Dong 2019 published cutoff is strictly below 3.90 (an EVendo score below 3.90 would have spared EGDs). magent does not invent extra risk classes or endoscopy-sparing percents.
- US conventional units only (AST U/L, platelets 10^3/µL, BUN mg/dL, hemoglobin g/dL). magent does not convert SI units.
- Ascites is a caller-assigned flag. magent does not examine the abdomen.

## Formula

```
A = (8.5 * inr) + (ast_u_l / 35); B = (platelets_k_ul / 150) + (bun_mg_dl / 20) + (hemoglobin_g_dl / 15); evendo = A / B + (1 if ascites else 0); cutoff strictly below 3.90 (Dong 2019)
```

## Citation

[Machine learning-based development and validation of a scoring system for screening high-risk esophageal varices](https://doi.org/10.1016/j.cgh.2019.01.025)
Dong TS, Kalani A, Aby ES, Le L, Luu K, Hauer M, Kamath R, Lindor KD, Tabibian JH
Clin Gastroenterol Hepatol. 2019;17(9):1894-1901.e1
DOI: [10.1016/j.cgh.2019.01.025](https://doi.org/10.1016/j.cgh.2019.01.025)

## Worked example

### INR 1.0, AST 35, platelets 150, BUN 20, hemoglobin 15, no ascites

Given: `ascites=false, ast_u_l=35, bun_mg_dl=20, hemoglobin_g_dl=15, inr=1.0, platelets_k_ul=150`

1. A = (8.5 × 1.0) + (35 / 35) = 8.5 + 1 = 9.5
2. B = (150 / 150) + (20 / 20) + (15 / 15) = 1 + 1 + 1 = 3
3. evendo = 9.5 / 3 + 0 = 3.166… → 3.17 (2 decimals)
4. 3.17 < 3.90 → below_cutoff_3_90 = true


### Same labs with ascites (score increases by 1)

Given: `ascites=true, ast_u_l=35, bun_mg_dl=20, hemoglobin_g_dl=15, inr=1.0, platelets_k_ul=150`

1. A and B are unchanged (9.5 and 3)
2. evendo = 9.5 / 3 + 1 = 4.166… → 4.17
3. 4.17 is not < 3.90 → below_cutoff_3_90 = false


## Also searched as

- EVendo
- EVendo score
- Dong EVendo
- esophageal varices score
- varices screening score
- EVendo INR AST platelets
- high-risk esophageal varices
- Dong 2019 varices score

## Parameters

- `inr` (number, required): International normalized ratio (0.8-4.0, magent clamp). Dong 2019 uses INR. Rejects non-positive INR. magent does not assay coagulation.
- `ast_u_l` (number, required): Aspartate aminotransferase in U/L (5-4000, magent clamp). US conventional units as in Dong 2019. Rejects non-positive AST. magent does not assay AST.
- `platelets_k_ul` (number, required): Platelet count in 10^3/µL (10-800, magent clamp), the same unit as 10^9/L. US conventional units as in Dong 2019. Rejects non-positive platelets. magent does not assay platelets.
- `bun_mg_dl` (number, required): Blood urea nitrogen in mg/dL (2-150, magent clamp). US conventional units as in Dong 2019. Rejects non-positive BUN. magent does not assay BUN.
- `hemoglobin_g_dl` (number, required): Hemoglobin in g/dL (4-20, magent clamp). US conventional units as in Dong 2019. Rejects non-positive hemoglobin. magent does not assay hemoglobin.
- `ascites` (boolean, required): Clinically evident ascites as assigned by the caller (Dong 2019). true adds 1 to the score; false adds 0. true or false. magent does not examine the abdomen.

## 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/evendo`
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": [
    {
      "ascites": "false",
      "ast_u_l": "35",
      "bun_mg_dl": "20",
      "hemoglobin_g_dl": "15",
      "inr": "1.0",
      "platelets_k_ul": "150"
    },
    {
      "ascites": "false",
      "ast_u_l": "35",
      "bun_mg_dl": "20",
      "hemoglobin_g_dl": "15",
      "inr": "1.0",
      "platelets_k_ul": "150"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/evendo",
  "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": "Dong TS, Kalani A, Aby ES, Le L, Luu K, Hauer M, Kamath R, Lindor KD, Tabibian JH",
        "doi": "10.1016/j.cgh.2019.01.025",
        "id": "dong-2019",
        "pmid": "30708109",
        "source": "Clin Gastroenterol Hepatol. 2019;17(9):1894-1901.e1",
        "title": "Machine learning-based development and validation of a scoring system for screening high-risk esophageal varices"
      },
      "formula": "evendo",
      "formula_expression": "A = (8.5 * inr) + (ast_u_l / 35); B = (platelets_k_ul / 150) + (bun_mg_dl / 20) + (hemoglobin_g_dl / 15); evendo = A / B + (1 if ascites else 0); cutoff strictly below 3.90 (Dong 2019)",
      "ast_u_l": 35.0,
      "inr": 1.0,
      "bun_mg_dl": 20.0,
      "hemoglobin_g_dl": 15.0,
      "ascites": false,
      "below_cutoff_3_90": true,
      "evendo": 3.17,
      "platelets_k_ul": 150.0
    },
    {
      "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": "Dong TS, Kalani A, Aby ES, Le L, Luu K, Hauer M, Kamath R, Lindor KD, Tabibian JH",
        "doi": "10.1016/j.cgh.2019.01.025",
        "id": "dong-2019",
        "pmid": "30708109",
        "source": "Clin Gastroenterol Hepatol. 2019;17(9):1894-1901.e1",
        "title": "Machine learning-based development and validation of a scoring system for screening high-risk esophageal varices"
      },
      "formula": "evendo",
      "formula_expression": "A = (8.5 * inr) + (ast_u_l / 35); B = (platelets_k_ul / 150) + (bun_mg_dl / 20) + (hemoglobin_g_dl / 15); evendo = A / B + (1 if ascites else 0); cutoff strictly below 3.90 (Dong 2019)",
      "ast_u_l": 35.0,
      "inr": 1.0,
      "bun_mg_dl": 20.0,
      "hemoglobin_g_dl": 15.0,
      "ascites": false,
      "below_cutoff_3_90": true,
      "evendo": 3.17,
      "platelets_k_ul": 150.0
    }
  ]
}
```

## Response fields

- `formula` (string): evendo
- `formula_expression` (string): Exact Dong 2019 expression
- `inr` (number): INR used in A
- `ast_u_l` (number): AST in U/L used in A
- `platelets_k_ul` (number): Platelets in 10^3/µL used in B
- `bun_mg_dl` (number): BUN in mg/dL used in B
- `hemoglobin_g_dl` (number): Hemoglobin in g/dL used in B
- `ascites` (boolean): Caller-assigned ascites used as the +1 term
- `evendo` (number): Dong 2019 EVendo score, 2 decimals. Not a varices diagnosis.
- `below_cutoff_3_90` (boolean): true when the rounded EVendo score is strictly below 3.90 (Dong 2019: an EVendo score below 3.90 would have spared EGDs). Not an endoscopy order.
- `citation` (object): Dong 2019 Clin Gastroenterol Hepatol citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "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": "Dong TS, Kalani A, Aby ES, Le L, Luu K, Hauer M, Kamath R, Lindor KD, Tabibian JH",
    "doi": "10.1016/j.cgh.2019.01.025",
    "id": "dong-2019",
    "pmid": "30708109",
    "source": "Clin Gastroenterol Hepatol. 2019;17(9):1894-1901.e1",
    "title": "Machine learning-based development and validation of a scoring system for screening high-risk esophageal varices"
  },
  "formula": "evendo",
  "formula_expression": "A = (8.5 * inr) + (ast_u_l / 35); B = (platelets_k_ul / 150) + (bun_mg_dl / 20) + (hemoglobin_g_dl / 15); evendo = A / B + (1 if ascites else 0); cutoff strictly below 3.90 (Dong 2019)",
  "ast_u_l": 35.0,
  "inr": 1.0,
  "bun_mg_dl": 20.0,
  "hemoglobin_g_dl": 15.0,
  "ascites": false,
  "below_cutoff_3_90": true,
  "evendo": 3.17,
  "platelets_k_ul": 150.0
}
```

## Errors

- HTTP 400 `invalid_evendo`: EVendo inputs must be numeric INR, AST, platelets, BUN, and hemoglobin plus ascites as used in Dong 2019. 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

- [Child–Pugh](https://magentlab.com/docs/child-pugh) — Compute the Child–Turcotte–Pugh cirrhosis severity score from bilirubin, albumin, INR, encephalopathy, and ascites.
- [MELD](https://magentlab.com/docs/meld) — Compute the Kamath 2001 model for end-stage liver disease (MELD) integer from creatinine, bilirubin, INR, and cholestatic or alcoholic etiology.

## 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.