# Anion gap Anion gap ## Also searched as - anion gap - serum anion gap - Na Cl HCO3 gap - anion gap with potassium - Emmett Narins anion gap - AG without K - AG with K Status: LIVE Price: $0.005 USDC `GET /api/calc/anion_gap` HTML: https://magentlab.com/docs/anion-gap Markdown: https://magentlab.com/docs/anion-gap.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Compute the serum anion gap from sodium, chloride, and bicarbonate, with or without potassium, using the Emmett–Narins 1977 formulas. formula is required. ## When to use When an agent needs a published anion gap and must not pick with-K vs without-K silently, assign high/low AG, or apply an albumin correction. ## When not to use - Not a diagnosis. magent does not assign a high or low anion gap. - Does not correct for albumin. Figge/Fencl albumin-corrected anion gap is not this tool. - Does not compute a delta gap. ## Formula ``` anion_gap_mmol_l = sodium_mmol_l - chloride_mmol_l - bicarbonate_mmol_l ``` ## Citation [Clinical use of the anion gap](https://doi.org/10.1097/00005792-197701000-00002) Emmett M, Narins RG Medicine (Baltimore). 1977;56(1):38-54 DOI: [10.1097/00005792-197701000-00002](https://doi.org/10.1097/00005792-197701000-00002) ## Worked example ### Na 140, Cl 104, HCO3 24 without K Given: `bicarbonate_mmol_l=24, chloride_mmol_l=104, formula=without_k, sodium_mmol_l=140` 1. anion_gap = 140 - 104 - 24 = 12.0 mmol/L ### Na 140, Cl 104, HCO3 24, K 4.0 with K Given: `bicarbonate_mmol_l=24, chloride_mmol_l=104, formula=with_k, potassium_mmol_l=4.0, sodium_mmol_l=140` 1. anion_gap = 140 + 4.0 - 104 - 24 = 16.0 mmol/L ## Parameters - `sodium_mmol_l` (number, required): Serum sodium in mmol/L (110-160). - `chloride_mmol_l` (number, required): Serum chloride in mmol/L (70-130). - `bicarbonate_mmol_l` (number, required): Serum bicarbonate in mmol/L (2-45). - `potassium_mmol_l` (number, optional): Serum potassium in mmol/L (1.5-8.0). Required when formula=with_k. Ignored when formula=without_k. - `formula` (string, required): without_k (Na - Cl - HCO3) or with_k (Na + K - Cl - HCO3). Required; magent does not pick one silently. ## Bulk (POST) POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/anion_gap` Max items: 25 Price: unit_amount * n (unit 5000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - 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": [ { "bicarbonate_mmol_l": "24", "chloride_mmol_l": "104", "formula": "without_k", "sodium_mmol_l": "140" }, { "bicarbonate_mmol_l": "24", "chloride_mmol_l": "104", "formula": "without_k", "sodium_mmol_l": "140" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/anion-gap Example 200: ```json { "count": 2, "path": "/api/calc/anion_gap", "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": "Emmett M, Narins RG", "doi": "10.1097/00005792-197701000-00002", "id": "emmett-narins-1977", "source": "Medicine (Baltimore). 1977;56(1):38-54", "title": "Clinical use of the anion gap" }, "formula": "without_k", "formula_expression": "anion_gap_mmol_l = sodium_mmol_l - chloride_mmol_l - bicarbonate_mmol_l", "anion_gap_mmol_l": 12.0, "bicarbonate_mmol_l": 24.0, "chloride_mmol_l": 104.0, "sodium_mmol_l": 140.0 }, { "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": "Emmett M, Narins RG", "doi": "10.1097/00005792-197701000-00002", "id": "emmett-narins-1977", "source": "Medicine (Baltimore). 1977;56(1):38-54", "title": "Clinical use of the anion gap" }, "formula": "without_k", "formula_expression": "anion_gap_mmol_l = sodium_mmol_l - chloride_mmol_l - bicarbonate_mmol_l", "anion_gap_mmol_l": 12.0, "bicarbonate_mmol_l": 24.0, "chloride_mmol_l": 104.0, "sodium_mmol_l": 140.0 } ] } ``` ## Response fields - `formula` (string): without_k or with_k - `formula_expression` (string): Exact expression used - `sodium_mmol_l` (number): Input sodium in mmol/L - `chloride_mmol_l` (number): Input chloride in mmol/L - `bicarbonate_mmol_l` (number): Input bicarbonate in mmol/L - `potassium_mmol_l` (number): Serum potassium used when formula=with_k. Omitted when formula=without_k. - `anion_gap_mmol_l` (number): Anion gap in mmol/L, 1 decimal - `citation` (object): Emmett and Narins 1977 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": "Emmett M, Narins RG", "doi": "10.1097/00005792-197701000-00002", "id": "emmett-narins-1977", "source": "Medicine (Baltimore). 1977;56(1):38-54", "title": "Clinical use of the anion gap" }, "formula": "without_k", "formula_expression": "anion_gap_mmol_l = sodium_mmol_l - chloride_mmol_l - bicarbonate_mmol_l", "anion_gap_mmol_l": 12.0, "bicarbonate_mmol_l": 24.0, "chloride_mmol_l": 104.0, "sodium_mmol_l": 140.0 } ``` ## Errors - HTTP 400 `invalid_sodium`: sodium_mmol_l must be a number from 110 to 160 Returned before settlement; you are not charged. - HTTP 400 `invalid_chloride`: chloride_mmol_l must be a number from 70 to 130. Returned before settlement; you are not charged. - HTTP 400 `invalid_bicarbonate`: bicarbonate_mmol_l must be a number from 2 to 45. Returned before settlement; you are not charged. - HTTP 400 `invalid_potassium`: potassium_mmol_l must be a number from 1.5 to 8.0. Returned before settlement; you are not charged. - HTTP 400 `invalid_anion_gap_formula`: formula must be without_k or with_k. 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 - [Winters' formula](https://magentlab.com/docs/winters) — Compute expected arterial PCO2 in metabolic acidosis from plasma bicarbonate using the Albert–Winters 1967 formula. - [Serum osmolality](https://magentlab.com/docs/serum-osmolality) — Compute Worthley calculated serum osmolality from sodium, glucose, and BUN, plus an optional osmolar gap when a measured osm is supplied. ## Payment Required query parameters must be present and valid. 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 EIP-3009 (scheme exact, assetTransferMethod eip3009) with validBefore = now + accepts[0].maxTimeoutSeconds (600 seconds). That window starts when you sign and must cover wallet confirmation plus CDP verify and settle. Magent retries transient facilitator 429/5xx before answering. Do not send upto or batch-settlement payloads; magent does not offer those schemes. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON echoing accepted, payload, and extensions when present). - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. Settlement happens before the tool runs. HTTP 503 settlement_uncertain or settle_failed: retry the same PAYMENT-SIGNATURE. Mint a new 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. - 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. - not offered `batch-settlement`: Not offered. Payment-channel vouchers claimed later in batches. Not the same as POST {items} bulk (that is still exact). Same-path POST {items} is still scheme exact: one EIP-3009 authorization for n times the GET unit. 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 - Invalid query parameters return HTTP 400 before settlement. You are not charged. - Settlement finishes before the tool executes (paymentFlow upfront). 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.