# Menza HIV acquisition score

Menza

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

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

## What it computes

Sum the four Menza 2009 caller-assigned flags and return the 0–19 point total.

## When to use

When an agent has already assigned the four Menza 2009 flags and needs the published point total. magent does not take a sexual history and does not diagnose HIV, order PrEP, or run a test-and-treat protocol.

## When not to use

- Not a medical device.
- Not a diagnosis of HIV infection.
- Not a PrEP order and not a test-and-treat protocol.
- magent does not take a sexual history. Each flag is caller-assigned.
- This is Menza 2009 only. Not HIRI-MSM and not SexPro.
- Menza 2009 did not publish named low/high strata or PrEP cutoffs; magent returns the integer score only.

## Formula

```
Menza = meth_or_poppers_6mo (true 11) + bacterial_sti (true 4) + partners_ge_10_year (true 3) + uai_positive_or_unknown_year (true 1); Menza 2009; max 19
```

## Citation

[Prediction of HIV acquisition among men who have sex with men](https://doi.org/10.1097/OLQ.0b013e3181a9cc41)
Menza TW, Hughes JP, Celum CL, Golden MR
Sex Transm Dis. 2009;36(9):547-555
DOI: [10.1097/OLQ.0b013e3181a9cc41](https://doi.org/10.1097/OLQ.0b013e3181a9cc41)

## Worked example

### All four flags false

Given: `bacterial_sti=false, meth_or_poppers_6mo=false, partners_ge_10_year=false, uai_positive_or_unknown_year=false`

1. meth_or_poppers_6mo false → 0; bacterial_sti false → 0; partners_ge_10_year false → 0; uai_positive_or_unknown_year false → 0
2. Score = 0 (max 19)


### All four flags true

Given: `bacterial_sti=true, meth_or_poppers_6mo=true, partners_ge_10_year=true, uai_positive_or_unknown_year=true`

1. meth_or_poppers_6mo true → 11; bacterial_sti true → 4; partners_ge_10_year true → 3; uai_positive_or_unknown_year true → 1
2. Score = 19 (max 19)


## Also searched as

- Menza score
- Menza 2009
- HIV acquisition MSM
- MSM HIV risk score
- methamphetamine poppers STI
- Menza HIV prediction
- ten or more male partners HIV

## Parameters

- `meth_or_poppers_6mo` (boolean, required): Methamphetamine or inhaled nitrites (poppers) in the prior 6 months as assigned by the caller (Menza 2009). true scores 11. magent does not take a sexual history.
- `bacterial_sti` (boolean, required): Current diagnosis or history of bacterial STI (Menza 2009: gonorrhea, chlamydia, or syphilis) as assigned by the caller. true scores 4. magent does not take a sexual history.
- `partners_ge_10_year` (boolean, required): Ten or more male sex partners in the prior year as assigned by the caller (Menza 2009). true scores 3. magent does not take a sexual history.
- `uai_positive_or_unknown_year` (boolean, required): Unprotected anal intercourse with a partner of positive or unknown HIV status in the prior year as assigned by the caller (Menza 2009). true scores 1. magent does not take a sexual history.

## 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/menza`
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": [
    {
      "bacterial_sti": "false",
      "meth_or_poppers_6mo": "false",
      "partners_ge_10_year": "false",
      "uai_positive_or_unknown_year": "false"
    },
    {
      "bacterial_sti": "false",
      "meth_or_poppers_6mo": "false",
      "partners_ge_10_year": "false",
      "uai_positive_or_unknown_year": "false"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/menza",
  "items": [
    {
      "components": [
        {
          "factor": "meth_or_poppers_6mo",
          "points": 0,
          "present": false
        },
        {
          "factor": "bacterial_sti",
          "points": 0,
          "present": false
        },
        {
          "factor": "partners_ge_10_year",
          "points": 0,
          "present": false
        },
        {
          "factor": "uai_positive_or_unknown_year",
          "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": "Menza TW, Hughes JP, Celum CL, Golden MR",
        "doi": "10.1097/OLQ.0b013e3181a9cc41",
        "id": "menza-2009",
        "pmid": "19707108",
        "source": "Sex Transm Dis. 2009;36(9):547-555",
        "title": "Prediction of HIV acquisition among men who have sex with men"
      },
      "formula": "menza",
      "formula_expression": "Menza = meth_or_poppers_6mo (true 11) + bacterial_sti (true 4) + partners_ge_10_year (true 3) + uai_positive_or_unknown_year (true 1); Menza 2009; max 19",
      "max_score": 19,
      "score": 0
    },
    {
      "components": [
        {
          "factor": "meth_or_poppers_6mo",
          "points": 0,
          "present": false
        },
        {
          "factor": "bacterial_sti",
          "points": 0,
          "present": false
        },
        {
          "factor": "partners_ge_10_year",
          "points": 0,
          "present": false
        },
        {
          "factor": "uai_positive_or_unknown_year",
          "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": "Menza TW, Hughes JP, Celum CL, Golden MR",
        "doi": "10.1097/OLQ.0b013e3181a9cc41",
        "id": "menza-2009",
        "pmid": "19707108",
        "source": "Sex Transm Dis. 2009;36(9):547-555",
        "title": "Prediction of HIV acquisition among men who have sex with men"
      },
      "formula": "menza",
      "formula_expression": "Menza = meth_or_poppers_6mo (true 11) + bacterial_sti (true 4) + partners_ge_10_year (true 3) + uai_positive_or_unknown_year (true 1); Menza 2009; max 19",
      "max_score": 19,
      "score": 0
    }
  ]
}
```

## Response fields

- `formula` (string): menza
- `formula_expression` (string): Exact expression used
- `score` (integer): Menza 2009 points 0-19
- `max_score` (integer): 19
- `components` (array): Per-flag points
- `citation` (object): Menza et al. Sex Transm Dis 2009 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "factor": "meth_or_poppers_6mo",
      "points": 0,
      "present": false
    },
    {
      "factor": "bacterial_sti",
      "points": 0,
      "present": false
    },
    {
      "factor": "partners_ge_10_year",
      "points": 0,
      "present": false
    },
    {
      "factor": "uai_positive_or_unknown_year",
      "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": "Menza TW, Hughes JP, Celum CL, Golden MR",
    "doi": "10.1097/OLQ.0b013e3181a9cc41",
    "id": "menza-2009",
    "pmid": "19707108",
    "source": "Sex Transm Dis. 2009;36(9):547-555",
    "title": "Prediction of HIV acquisition among men who have sex with men"
  },
  "formula": "menza",
  "formula_expression": "Menza = meth_or_poppers_6mo (true 11) + bacterial_sti (true 4) + partners_ge_10_year (true 3) + uai_positive_or_unknown_year (true 1); Menza 2009; max 19",
  "max_score": 19,
  "score": 0
}
```

## Errors

- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false 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

- [HIRI-MSM](https://magentlab.com/docs/hiri-msm) — Sum the published Smith 2012 seven-item HIV incidence risk index for MSM (age plus six prior-6-month behaviors, 0–47) and return at_or_above_10 when the total is ≥10.
- [CAGE](https://magentlab.com/docs/cage) — Sum the four Ewing 1984 CAGE items and return whether two or more answers are affirmative.

## 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.