# RBC ABO/Rh compatibility (AABB)

RBC ABO/Rh compatibility (AABB)

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

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

## What it computes

Apply AABB Standards for Blood Banks and Transfusion Services Standard 5.14 ABO/Rh compatibility of RBC units from caller-assigned recipient and unit ABO and RhD, and return compatible, abo_compatible, and rhd_compatible.

## When to use

When an agent already has caller-assigned recipient and unit ABO group and RhD and needs AABB Standard 5.14 RBC compatibility, and must not invent an emergency RhD-positive-to-negative exception, a plasma or platelet rule, or an antibody-screen formula.

## When not to use

- Not a medical device. Not a transfusion order.
- magent does not type blood. recipient_abo, recipient_rhd, unit_abo, and unit_rhd are caller-assigned.
- AABB Standard 5.14 RBC ABO/Rh compatibility only. Does not encode emergency RhD-positive-to-negative exceptions, plasma or platelet compatibility, or antibody-screen units-to-crossmatch formulas.

## Formula

```
compatible iff abo_compatible and rhd_compatible. RBC ABO: unit o → recipient o|a|b|ab; unit a → a|ab; unit b → b|ab; unit ab → ab. RhD: unit negative → recipient negative|positive; unit positive → recipient positive only (AABB Standards 28th ed. Standard 5.14). Not an emergency RhD-positive-to-negative exception. Not plasma or platelets. magent does not type blood
```

## Citation

[Standards for Blood Banks and Transfusion Services](https://www.worldcat.org/isbn/9781563958380)
AABB
28th ed. Bethesda, MD: AABB; 2012. Standard 5.14
DOI: none

## Worked example

### Recipient O RhD-negative, unit O RhD-negative

Given: `recipient_abo=o, recipient_rhd=negative, unit_abo=o, unit_rhd=negative`

1. unit ABO o to recipient o (O RBCs to O/A/B/AB) → abo_compatible true
2. unit RhD negative to recipient negative → rhd_compatible true
3. compatible = abo_compatible and rhd_compatible = true


## Also searched as

- RBC ABO compatibility
- ABO RhD compatibility
- AABB RBC compatibility
- red cell ABO Rh
- compatible RBC units
- ABO compatible red cells
- RhD compatible RBCs

## Parameters

- `recipient_abo` (string, required): Caller-assigned recipient ABO group: o, a, b, or ab (case-insensitive). Required. magent does not type blood.
- `recipient_rhd` (string, required): Caller-assigned recipient RhD: positive or negative (case-insensitive). Required. magent does not type blood.
- `unit_abo` (string, required): Caller-assigned RBC unit ABO group: o, a, b, or ab (case-insensitive). Required. magent does not type blood.
- `unit_rhd` (string, required): Caller-assigned RBC unit RhD: positive or negative (case-insensitive). Required. magent does not type blood.

## 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/rbc_abo`
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": [
    {
      "recipient_abo": "o",
      "recipient_rhd": "negative",
      "unit_abo": "o",
      "unit_rhd": "negative"
    },
    {
      "recipient_abo": "o",
      "recipient_rhd": "negative",
      "unit_abo": "o",
      "unit_rhd": "negative"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rbc_abo",
  "items": [
    {
      "compatible": true,
      "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": "AABB",
        "id": "aabb-rbc-abo-compatibility",
        "source": "28th ed. Bethesda, MD: AABB; 2012. Standard 5.14",
        "title": "Standards for Blood Banks and Transfusion Services"
      },
      "formula": "rbc_abo",
      "formula_expression": "compatible iff abo_compatible and rhd_compatible. RBC ABO: unit o → recipient o|a|b|ab; unit a → a|ab; unit b → b|ab; unit ab → ab. RhD: unit negative → recipient negative|positive; unit positive → recipient positive only (AABB Standards 28th ed. Standard 5.14). Not an emergency RhD-positive-to-negative exception. Not plasma or platelets. magent does not type blood",
      "criteria": [
        {
          "factor": "abo_compatible",
          "met": true
        },
        {
          "factor": "rhd_compatible",
          "met": true
        }
      ],
      "abo_compatible": true,
      "recipient_abo": "o",
      "recipient_rhd": "negative",
      "rhd_compatible": true,
      "unit_abo": "o",
      "unit_rhd": "negative"
    },
    {
      "compatible": true,
      "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": "AABB",
        "id": "aabb-rbc-abo-compatibility",
        "source": "28th ed. Bethesda, MD: AABB; 2012. Standard 5.14",
        "title": "Standards for Blood Banks and Transfusion Services"
      },
      "formula": "rbc_abo",
      "formula_expression": "compatible iff abo_compatible and rhd_compatible. RBC ABO: unit o → recipient o|a|b|ab; unit a → a|ab; unit b → b|ab; unit ab → ab. RhD: unit negative → recipient negative|positive; unit positive → recipient positive only (AABB Standards 28th ed. Standard 5.14). Not an emergency RhD-positive-to-negative exception. Not plasma or platelets. magent does not type blood",
      "criteria": [
        {
          "factor": "abo_compatible",
          "met": true
        },
        {
          "factor": "rhd_compatible",
          "met": true
        }
      ],
      "abo_compatible": true,
      "recipient_abo": "o",
      "recipient_rhd": "negative",
      "rhd_compatible": true,
      "unit_abo": "o",
      "unit_rhd": "negative"
    }
  ]
}
```

## Response fields

- `formula` (string): rbc_abo
- `formula_expression` (string): AABB Standard 5.14 RBC ABO/Rh compatibility rule
- `recipient_abo` (string): Echo of caller-assigned recipient ABO (o, a, b, or ab)
- `recipient_rhd` (string): Echo of caller-assigned recipient RhD (positive or negative)
- `unit_abo` (string): Echo of caller-assigned unit ABO (o, a, b, or ab)
- `unit_rhd` (string): Echo of caller-assigned unit RhD (positive or negative)
- `abo_compatible` (boolean): true when the unit ABO is ABO-compatible for RBC transfusion to the recipient
- `rhd_compatible` (boolean): true when the unit RhD is compatible: RhD-negative units to either RhD; RhD-positive units only to RhD-positive recipients
- `compatible` (boolean): true only when both abo_compatible and rhd_compatible hold
- `criteria` (array): Per-factor rows with factor and met for ABO and RhD
- `citation` (object): AABB Standards 28th ed. Standard 5.14 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "compatible": true,
  "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": "AABB",
    "id": "aabb-rbc-abo-compatibility",
    "source": "28th ed. Bethesda, MD: AABB; 2012. Standard 5.14",
    "title": "Standards for Blood Banks and Transfusion Services"
  },
  "formula": "rbc_abo",
  "formula_expression": "compatible iff abo_compatible and rhd_compatible. RBC ABO: unit o → recipient o|a|b|ab; unit a → a|ab; unit b → b|ab; unit ab → ab. RhD: unit negative → recipient negative|positive; unit positive → recipient positive only (AABB Standards 28th ed. Standard 5.14). Not an emergency RhD-positive-to-negative exception. Not plasma or platelets. magent does not type blood",
  "criteria": [
    {
      "factor": "abo_compatible",
      "met": true
    },
    {
      "factor": "rhd_compatible",
      "met": true
    }
  ],
  "abo_compatible": true,
  "recipient_abo": "o",
  "recipient_rhd": "negative",
  "rhd_compatible": true,
  "unit_abo": "o",
  "unit_rhd": "negative"
}
```

## Errors

- HTTP 400 `invalid_rbc_abo`: RBC ABO/Rh compatibility inputs must match caller-assigned recipient and unit ABO group and RhD. 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

- [Plasma starting dose](https://magentlab.com/docs/plasma-dosage) — Compute the BSH Green 2018 starting plasma volume from body weight: 15 mL/kg in the absence of major bleeding. Adult starting dose only.
- [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.