# Rebound hyperbilirubinemia score

Rebound hyperbilirubinemia

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

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

## What it computes

Return the Chang 2017 three-variable rebound hyperbilirubinemia prediction score after inpatient phototherapy from gestational age, age at phototherapy initiation in days, TSB at termination, and a caller-supplied AAP phototherapy threshold. Scores <20 correspond to a <4% probability of rebound in that paper.

## When to use

When an agent already has gestational age, age at phototherapy initiation, TSB at termination, and the AAP phototherapy threshold and needs the published Chang 2017 three-variable score. magent does not assay bilirubin, compute the AAP nomogram, or order phototherapy.

## When not to use

- Not a medical device and not a phototherapy order. magent does not assay bilirubin or compute the AAP phototherapy nomogram.
- This is Chang 2017's three-variable integer prediction score only (gestational age <38 weeks, age at phototherapy initiation in days, TSB relative to the caller-supplied AAP phototherapy threshold). It is not Chang 2019's two-variable score.
- Scores <20 correspond to a <4% probability of rebound (TSB back to phototherapy threshold within 72 hours) in Chang 2017. magent does not emit other named risk classes or a logistic probability.
- The derivation cohort was gestational age ≥35 weeks with phototherapy before age 14 days. Age is in days (fractional allowed); magent does not convert hours.

## Formula

```
score = (15 if gestational_age_weeks < 38 else 0) - 7 × age_at_initiation_days - 4 × (phototherapy_threshold_mg_dl − tsb_at_termination_mg_dl) + 50; Chang 2017 three-variable integer prediction score; scores <20 correspond to a <4% probability of rebound (TSB back to phototherapy threshold within 72 hours)
```

## Citation

[A Clinical Prediction Rule for Rebound Hyperbilirubinemia Following Inpatient Phototherapy](https://doi.org/10.1542/peds.2016-2896)
Chang PW, Kuzniewicz MW, McCulloch CE, Newman TB
Pediatrics. 2017;139(3):e20162896
DOI: [10.1542/peds.2016-2896](https://doi.org/10.1542/peds.2016-2896)

## Worked example

### Term 39 weeks, phototherapy day 3, TSB 12, threshold 16

Given: `age_at_initiation_days=3, gestational_age_weeks=39, phototherapy_threshold_mg_dl=16, tsb_at_termination_mg_dl=12`

1. Gestational age 39 ≥ 38 → 0
2. 0 − 7 × 3 − 4 × (16 − 12) + 50 = 13
3. Score = 13; score_lt_20 true (<4% rebound probability in Chang 2017)


### Same numbers at 37 weeks (adds 15)

Given: `age_at_initiation_days=3, gestational_age_weeks=37, phototherapy_threshold_mg_dl=16, tsb_at_termination_mg_dl=12`

1. Gestational age 37 < 38 → 15
2. 15 − 7 × 3 − 4 × (16 − 12) + 50 = 28
3. Score = 28; score_lt_20 false


### Term 39 weeks, phototherapy day 2, TSB 12, threshold 16 (score 20)

Given: `age_at_initiation_days=2, gestational_age_weeks=39, phototherapy_threshold_mg_dl=16, tsb_at_termination_mg_dl=12`

1. Gestational age 39 ≥ 38 → 0
2. 0 − 7 × 2 − 4 × (16 − 12) + 50 = 20
3. Score = 20; score_lt_20 false (not <20)


## Also searched as

- rebound hyperbilirubinemia
- Chang 2017 rebound score
- rebound bilirubin after phototherapy
- phototherapy rebound score
- neonatal rebound hyperbilirubinemia
- TSB rebound prediction
- Chang three-variable rebound score

## Parameters

- `gestational_age_weeks` (integer, required): Gestational age in completed weeks, integer 35-45. Chang 2017 cohort was ≥35 weeks. Scores +15 when <38 weeks; 38 weeks and above score 0. magent does not convert days.
- `age_at_initiation_days` (number, required): Chronologic age at phototherapy initiation in days (0-14; fractional days allowed). Chang 2017 treated infants before age 14 days. magent does not convert hours.
- `tsb_at_termination_mg_dl` (number, required): Total serum bilirubin at phototherapy termination in mg/dL (0-40). magent does not assay bilirubin.
- `phototherapy_threshold_mg_dl` (number, required): Caller-supplied AAP phototherapy threshold in mg/dL at termination (0-40). Difference is (threshold − TSB) and may be negative if TSB is still above threshold. magent does not compute the AAP nomogram.

## 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/rebound_hyperbilirubinemia`
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": [
    {
      "age_at_initiation_days": "3",
      "gestational_age_weeks": "39",
      "phototherapy_threshold_mg_dl": "16",
      "tsb_at_termination_mg_dl": "12"
    },
    {
      "age_at_initiation_days": "3",
      "gestational_age_weeks": "39",
      "phototherapy_threshold_mg_dl": "16",
      "tsb_at_termination_mg_dl": "12"
    }
  ]
}
```

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

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rebound_hyperbilirubinemia",
  "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": "Chang PW, Kuzniewicz MW, McCulloch CE, Newman TB",
        "doi": "10.1542/peds.2016-2896",
        "id": "chang-2017",
        "pmid": "28196932",
        "source": "Pediatrics. 2017;139(3):e20162896",
        "title": "A Clinical Prediction Rule for Rebound Hyperbilirubinemia Following Inpatient Phototherapy"
      },
      "formula": "rebound_hyperbilirubinemia",
      "formula_expression": "score = (15 if gestational_age_weeks < 38 else 0) - 7 × age_at_initiation_days - 4 × (phototherapy_threshold_mg_dl − tsb_at_termination_mg_dl) + 50; Chang 2017 three-variable integer prediction score; scores <20 correspond to a <4% probability of rebound (TSB back to phototherapy threshold within 72 hours)",
      "score": 13,
      "age_at_initiation_days": 3.0,
      "gestational_age_weeks": 39,
      "phototherapy_threshold_mg_dl": 16.0,
      "score_lt_20": true,
      "tsb_at_termination_mg_dl": 12.0
    },
    {
      "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": "Chang PW, Kuzniewicz MW, McCulloch CE, Newman TB",
        "doi": "10.1542/peds.2016-2896",
        "id": "chang-2017",
        "pmid": "28196932",
        "source": "Pediatrics. 2017;139(3):e20162896",
        "title": "A Clinical Prediction Rule for Rebound Hyperbilirubinemia Following Inpatient Phototherapy"
      },
      "formula": "rebound_hyperbilirubinemia",
      "formula_expression": "score = (15 if gestational_age_weeks < 38 else 0) - 7 × age_at_initiation_days - 4 × (phototherapy_threshold_mg_dl − tsb_at_termination_mg_dl) + 50; Chang 2017 three-variable integer prediction score; scores <20 correspond to a <4% probability of rebound (TSB back to phototherapy threshold within 72 hours)",
      "score": 13,
      "age_at_initiation_days": 3.0,
      "gestational_age_weeks": 39,
      "phototherapy_threshold_mg_dl": 16.0,
      "score_lt_20": true,
      "tsb_at_termination_mg_dl": 12.0
    }
  ]
}
```

## Response fields

- `formula` (string): rebound_hyperbilirubinemia
- `formula_expression` (string): Exact Chang 2017 expression used
- `gestational_age_weeks` (integer): Completed gestational age in weeks
- `age_at_initiation_days` (number): Age at phototherapy initiation in days
- `tsb_at_termination_mg_dl` (number): TSB at phototherapy termination in mg/dL
- `phototherapy_threshold_mg_dl` (number): Caller-supplied AAP phototherapy threshold in mg/dL
- `score` (number): Chang 2017 three-variable prediction score, 1 decimal when not an exact integer
- `score_lt_20` (boolean): true when score < 20 (Chang 2017: <4% probability of rebound). Not a named risk class beyond that published cut.
- `citation` (object): Chang et al. Pediatrics 2017 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": "Chang PW, Kuzniewicz MW, McCulloch CE, Newman TB",
    "doi": "10.1542/peds.2016-2896",
    "id": "chang-2017",
    "pmid": "28196932",
    "source": "Pediatrics. 2017;139(3):e20162896",
    "title": "A Clinical Prediction Rule for Rebound Hyperbilirubinemia Following Inpatient Phototherapy"
  },
  "formula": "rebound_hyperbilirubinemia",
  "formula_expression": "score = (15 if gestational_age_weeks < 38 else 0) - 7 × age_at_initiation_days - 4 × (phototherapy_threshold_mg_dl − tsb_at_termination_mg_dl) + 50; Chang 2017 three-variable integer prediction score; scores <20 correspond to a <4% probability of rebound (TSB back to phototherapy threshold within 72 hours)",
  "score": 13,
  "age_at_initiation_days": 3.0,
  "gestational_age_weeks": 39,
  "phototherapy_threshold_mg_dl": 16.0,
  "score_lt_20": true,
  "tsb_at_termination_mg_dl": 12.0
}
```

## Errors

- HTTP 400 `invalid_rebound_hyperbilirubinemia`: Rebound hyperbilirubinemia score inputs must match Chang 2017 gestational age, phototherapy timing, and bilirubin-relative-to-threshold terms from that paper. 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

- [Apgar score](https://magentlab.com/docs/apgar) — Compute the Apgar newborn evaluation score as the sum of five caller-assigned 0-2 signs.

## 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.