# Reticulocyte index

Reticulocyte index

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

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

## What it computes

Compute corrected reticulocyte count, a Hillman 1969 maturation-shift reticulocyte index, and optional absolute reticulocyte count from percent reticulocytes, hematocrit, and RBC.

## When to use

When an agent needs CRC, RI, or ARC from a CBC and must not invent a marrow-production diagnosis.

## When not to use

- Not a diagnosis of hypoproliferative versus hemolytic anemia. Maturation days 1.0/1.5/2.0/2.5 are a discrete reading of Hillman 1969 shift versus hematocrit (≥40, ≥30, ≥20, else), not a measured marrow transit time.
- ARC is omitted unless rbc_million_ul is provided. Does not convert an automated absolute reticulocyte count already reported by the lab.

## Formula

```
CRC = reticulocyte_percent * (hematocrit_percent / 45); RI = CRC / maturation_days; ARC_per_uL = reticulocyte_percent/100 * rbc_million_ul * 1e6 when RBC is given
```

## Citation

[Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia](https://doi.org/10.1172/JCI106002)
Hillman RS
J Clin Invest. 1969;48(3):443-453
DOI: [10.1172/JCI106002](https://doi.org/10.1172/JCI106002)

## Worked example

### Retic 2%, Hct 45, RBC 5.0 million/µL

Given: `hematocrit_percent=45, rbc_million_ul=5.0, reticulocyte_percent=2.0`

1. CRC = 2.0 × (45/45) = 2.00
2. maturation_days = 1.0 (Hct ≥40)
3. RI = 2.00 / 1.0 = 2.00
4. ARC = 0.02 × 5.0 × 1e6 = 100000 /µL


### Retic 10%, Hct 25, RBC omitted

Given: `hematocrit_percent=25, reticulocyte_percent=10.0`

1. CRC = 10.0 × (25/45) = 5.56
2. maturation_days = 2.0 (Hct ≥20 and <30)
3. RI = 5.56 / 2.0 = 2.78
4. ARC omitted


## Also searched as

- reticulocyte index
- corrected reticulocyte count
- absolute reticulocyte count
- ARC
- CRC
- Hillman reticulocyte

## Parameters

- `reticulocyte_percent` (number, required): Reticulocyte percent of RBC (0.1-30).
- `hematocrit_percent` (number, required): Hematocrit as a percent (10-70). CRC uses Hct/45. Maturation days: ≥40 → 1.0; ≥30 → 1.5; ≥20 → 2.0; else 2.5 (Hillman 1969 shift discretized).
- `rbc_million_ul` (number, optional): RBC count in 10^6/µL (1.0-8.0). When provided, ARC_per_uL is returned. Omitted omits ARC.

## 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/reticulocyte_index`
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": [
    {
      "hematocrit_percent": "45",
      "rbc_million_ul": "5.0",
      "reticulocyte_percent": "2.0"
    },
    {
      "hematocrit_percent": "45",
      "rbc_million_ul": "5.0",
      "reticulocyte_percent": "2.0"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/reticulocyte_index",
  "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": "Hillman RS",
        "doi": "10.1172/JCI106002",
        "id": "hillman-1969",
        "source": "J Clin Invest. 1969;48(3):443-453",
        "title": "Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia"
      },
      "formula": "reticulocyte_index",
      "formula_expression": "CRC = reticulocyte_percent * (hematocrit_percent / 45); RI = CRC / maturation_days; ARC_per_uL = reticulocyte_percent/100 * rbc_million_ul * 1e6 when RBC is given",
      "corrected_reticulocyte_percent": 2.0,
      "hematocrit_percent": 45.0,
      "maturation_days": 1.0,
      "reticulocyte_index": 2.0,
      "reticulocyte_percent": 2.0,
      "arc_per_ul": 100000
    },
    {
      "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": "Hillman RS",
        "doi": "10.1172/JCI106002",
        "id": "hillman-1969",
        "source": "J Clin Invest. 1969;48(3):443-453",
        "title": "Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia"
      },
      "formula": "reticulocyte_index",
      "formula_expression": "CRC = reticulocyte_percent * (hematocrit_percent / 45); RI = CRC / maturation_days; ARC_per_uL = reticulocyte_percent/100 * rbc_million_ul * 1e6 when RBC is given",
      "corrected_reticulocyte_percent": 2.0,
      "hematocrit_percent": 45.0,
      "maturation_days": 1.0,
      "reticulocyte_index": 2.0,
      "reticulocyte_percent": 2.0,
      "arc_per_ul": 100000
    }
  ]
}
```

## Response fields

- `formula` (string): reticulocyte_index
- `formula_expression` (string): Exact expression used
- `reticulocyte_percent` (number): Reticulocyte percent used
- `hematocrit_percent` (number): Hematocrit percent used
- `corrected_reticulocyte_percent` (number): CRC = retic% × (Hct/45), 2 decimals
- `maturation_days` (number): Hillman-style shift: 1.0, 1.5, 2.0, or 2.5 days
- `reticulocyte_index` (number): CRC / maturation_days, 2 decimals
- `arc_per_ul` (integer): Absolute reticulocyte count in cells/µL when rbc_million_ul is provided
- `citation` (object): Hillman 1969 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": "Hillman RS",
    "doi": "10.1172/JCI106002",
    "id": "hillman-1969",
    "source": "J Clin Invest. 1969;48(3):443-453",
    "title": "Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia"
  },
  "formula": "reticulocyte_index",
  "formula_expression": "CRC = reticulocyte_percent * (hematocrit_percent / 45); RI = CRC / maturation_days; ARC_per_uL = reticulocyte_percent/100 * rbc_million_ul * 1e6 when RBC is given",
  "corrected_reticulocyte_percent": 2.0,
  "hematocrit_percent": 45.0,
  "maturation_days": 1.0,
  "reticulocyte_index": 2.0,
  "reticulocyte_percent": 2.0,
  "arc_per_ul": 100000
}
```

## Errors

- HTTP 400 `invalid_reticulocyte_percent`: reticulocyte_percent must be a number from 0.1 to 30. Returned before settlement; you are not charged.
- HTTP 400 `invalid_hematocrit`: hematocrit_percent must be a number from 10 to 70. Returned before settlement; you are not charged.
- HTTP 400 `invalid_rbc_million_ul`: rbc_million_ul must be a number from 1.0 to 8.0 when provided. 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

- [ANC](https://magentlab.com/docs/anc) — Compute absolute neutrophil count from WBC and neutrophil plus band percents, plus a Bodey 1966 granulocyte band.

## 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 echoing accepted, payload, and extensions when present).
- 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.
- 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.