# RhIG vials

RhIG vials

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

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

## What it computes

Compute ACOG Practice Bulletin 181 RhD immune globulin vial count from caller-assigned fetal-cell percent and maternal blood volume using AABB Technical Manual rounding of FMH/30.

## When to use

When an agent needs ACOG PB 181 vial arithmetic from a caller-assigned Kleihauer–Betke percent and maternal blood volume and must not invent a brand order, read a slide, or skip the AABB extra vial.

## When not to use

- Not a prescription or brand order. magent does not name a product, route, or timing.
- magent does not interpret Kleihauer–Betke slides. fetal_cells_percent is the percent assigned by the caller.
- maternal_blood_volume_ml is caller-assigned. magent does not compute Nadler estimated blood volume.
- Society-policy AABB rounding of whole-blood FMH / 30 only. magent does not convert a red-cell volume path or a flow-cytometry method.

## Formula

```
fmh_ml = fetal_cells_percent / 100 * maternal_blood_volume_ml; raw = fmh_ml / 30; vials = (frac(raw) >= 0.5 ? ceil(raw) : floor(raw)) + 1
```

## Citation

[Prevention of Rh D Alloimmunization](https://doi.org/10.1097/AOG.0000000000002232)
Committee on Practice Bulletins-Obstetrics
Obstet Gynecol. 2017;130(2):e57-e70
DOI: [10.1097/AOG.0000000000002232](https://doi.org/10.1097/AOG.0000000000002232)

## Worked example

### 0.4% cells, 5000 mL maternal volume

Given: `fetal_cells_percent=0.4, maternal_blood_volume_ml=5000`

1. fmh_ml = 0.4 / 100 * 5000 = 20 mL
2. raw = 20 / 30 = 0.667
3. frac 0.667 >= 0.5 → round up to 1, then add one → 2 vials


### 0% cells, 5000 mL maternal volume (standard dose)

Given: `fetal_cells_percent=0, maternal_blood_volume_ml=5000`

1. fmh_ml = 0 / 100 * 5000 = 0 mL
2. raw = 0 / 30 = 0
3. frac 0 < 0.5 → round down to 0, then add one → 1 vial (standard postpartum dose)


## Also searched as

- RhIG vials
- RhD immune globulin
- fetomaternal hemorrhage vials
- Kleihauer-Betke vial count
- ACOG RhIG
- 300 microgram RhIG
- FMH RhIG dose

## Parameters

- `fetal_cells_percent` (number, required): Caller-assigned Kleihauer–Betke fetal-cell percent (0-5). magent does not interpret slides.
- `maternal_blood_volume_ml` (number, required): Caller-assigned maternal blood volume in mL (3000-10000). magent does not compute Nadler EBV.

## 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/rhig`
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": [
    {
      "fetal_cells_percent": "0.4",
      "maternal_blood_volume_ml": "5000"
    },
    {
      "fetal_cells_percent": "0.4",
      "maternal_blood_volume_ml": "5000"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rhig",
  "items": [
    {
      "raw": 0.667,
      "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": "Committee on Practice Bulletins-Obstetrics",
        "doi": "10.1097/AOG.0000000000002232",
        "id": "acog-2017-181",
        "pmid": "28742673",
        "source": "Obstet Gynecol. 2017;130(2):e57-e70",
        "title": "Prevention of Rh D Alloimmunization"
      },
      "formula": "acog_pb_181",
      "formula_expression": "fmh_ml = fetal_cells_percent / 100 * maternal_blood_volume_ml; raw = fmh_ml / 30; vials = (frac(raw) >= 0.5 ? ceil(raw) : floor(raw)) + 1",
      "fetal_cells_percent": 0.4,
      "fmh_ml": 20.0,
      "maternal_blood_volume_ml": 5.0e3,
      "vial_micrograms": 300,
      "vials": 2
    },
    {
      "raw": 0.667,
      "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": "Committee on Practice Bulletins-Obstetrics",
        "doi": "10.1097/AOG.0000000000002232",
        "id": "acog-2017-181",
        "pmid": "28742673",
        "source": "Obstet Gynecol. 2017;130(2):e57-e70",
        "title": "Prevention of Rh D Alloimmunization"
      },
      "formula": "acog_pb_181",
      "formula_expression": "fmh_ml = fetal_cells_percent / 100 * maternal_blood_volume_ml; raw = fmh_ml / 30; vials = (frac(raw) >= 0.5 ? ceil(raw) : floor(raw)) + 1",
      "fetal_cells_percent": 0.4,
      "fmh_ml": 20.0,
      "maternal_blood_volume_ml": 5.0e3,
      "vial_micrograms": 300,
      "vials": 2
    }
  ]
}
```

## Response fields

- `formula` (string): acog_pb_181
- `formula_expression` (string): FMH whole-blood formula and AABB vial rounding
- `fetal_cells_percent` (number): Caller-assigned Kleihauer–Betke percent used
- `maternal_blood_volume_ml` (number): Caller-assigned maternal blood volume in mL
- `fmh_ml` (number): Fetomaternal hemorrhage in mL of whole blood, 1 decimal
- `raw` (number): fmh_ml / 30 before AABB rounding, 3 decimals
- `vials` (integer): 300 microgram RhD immune globulin vials after AABB rounding
- `vial_micrograms` (integer): ACOG PB 181 standard vial size (300 micrograms)
- `citation` (object): ACOG Practice Bulletin 181 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "raw": 0.667,
  "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": "Committee on Practice Bulletins-Obstetrics",
    "doi": "10.1097/AOG.0000000000002232",
    "id": "acog-2017-181",
    "pmid": "28742673",
    "source": "Obstet Gynecol. 2017;130(2):e57-e70",
    "title": "Prevention of Rh D Alloimmunization"
  },
  "formula": "acog_pb_181",
  "formula_expression": "fmh_ml = fetal_cells_percent / 100 * maternal_blood_volume_ml; raw = fmh_ml / 30; vials = (frac(raw) >= 0.5 ? ceil(raw) : floor(raw)) + 1",
  "fetal_cells_percent": 0.4,
  "fmh_ml": 20.0,
  "maternal_blood_volume_ml": 5.0e3,
  "vial_micrograms": 300,
  "vials": 2
}
```

## Errors

- HTTP 400 `invalid_rhig`: RhIG vial arithmetic must match ACOG Practice Bulletin 181 fetal-cell percent and maternal blood volume from that bulletin. 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

- [Pregnancy due date from LMP](https://magentlab.com/docs/pregnancy-due-dates) — Return ACOG Committee Opinion 700 Naegele estimated due date in days from a certain last menstrual period, adjusting the 280-day interval when cycle length is not 28 days.
- [Morphine milligram equivalents](https://magentlab.com/docs/mme) — Compute morphine milligram equivalents from a CDC 2022 table opioid and daily dose (or transdermal fentanyl mcg/hr).
- [Allowable blood loss](https://magentlab.com/docs/allowable-blood-loss) — Compute Gross 1983 dilution-corrected allowable blood loss from a caller-supplied estimated blood volume and initial versus target hematocrit.

## 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.