# WHO 2016 Systemic Mastocytosis Criteria Calculator (magent)

> WHO 2016 Systemic Mastocytosis Criteria Calculator (magent) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Evaluates caller-assigned boolean findings against WHO 2016 (Valent 2016 Table 1) criteria to determine whether systemic mastocytosis diagnostic criteria are met.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/who_sm
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/who-2016-systemic-mastocytosis-criteria-calculator-magent-dc49b4ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SL1HxRzhJCKdbaqmeLXZx

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability who-2016-systemic-mastocytosis-criteria-calculator-magent-dc49b4ad
```

Example prompt: Does this patient meet WHO 2016 systemic mastocytosis criteria? They have major bone marrow infiltrates, more than 25% atypical spindle mast cells, a KIT codon 816 mutation, and CD25 expression — no associated myeloid neoplasm, and tryptase is above 20.

## When to prefer this

Use this endpoint when you have already gathered structured boolean findings from clinical reports (biopsy, flow cytometry, KIT sequencing, tryptase assay) and need to apply the WHO 2016 (Valent 2016 Table 1) algorithm programmatically. Prefer it over manual rule application whenever automating hematology diagnostic workflows. Not appropriate for ICC 2022 criteria, cutaneous mastocytosis only, or when raw lab values or pathology images need to be interpreted — the caller must pre-assign all boolean inputs.

## Known failure modes

- Missing required boolean parameters returns a validation error
- All inputs false returns criteria not met with zero minors
- tryptase_gt_20 true with associated_myeloid_neoplasm true silently excluded from minor count (expected behavior, not an error)
- Misclassification risk if caller assigns biopsy/lab findings incorrectly — the API does not validate clinical data

## How this service works

WHO 2016 systemic mastocytosis (Valent 2016 Table 1). Met when major infiltrates (≥15 mast cells in aggregates in BM or extracutaneous organ) plus ≥1 minor, or ≥3 minors. Minors: >25% atypical/spindle mast cells, KIT codon 816, CD2 and/or CD25, tryptase >20 ng/mL (not valid with an unrelated myeloid neoplasm). Not a diagnosis. Not cutaneous mastocytosis only. Not ICC 2022. magent does not read a biopsy or assay tryptase.

## Output

Returns whether WHO 2016 systemic mastocytosis criteria are met (true/false), along with the count and identity of satisfied major and minor criteria, applying the rule that tryptase >20 does not count as a minor when an associated myeloid neoplasm is present.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "major_infiltrates",
      "atypical_or_spindle",
      "kit_codon_816",
      "cd2_or_cd25",
      "tryptase_gt_20",
      "associated_myeloid_neoplasm"
     ],
     "properties": {
      "cd2_or_cd25": {
       "type": "boolean",
       "description": "Mast cells in bone marrow, blood, or another extracutaneous organ exhibit CD2 and/or CD25, as assigned by the caller (Valent 2016 Table 1 minor c). true or false. magent does not phenotype mast cells."
      },
      "kit_codon_816": {
       "type": "boolean",
       "description": "KIT point mutation at codon 816 in bone marrow or another extracutaneous organ, as assigned by the caller (Valent 2016 Table 1 minor b). true or false. magent does not sequence KIT."
      },
      "tryptase_gt_20": {
       "type": "boolean",
       "description": "Baseline serum tryptase >20 ng/mL as assigned by the caller (Valent 2016 Table 1 minor d). Does not count when associated_myeloid_neoplasm is true. true or false. magent does not assay tryptase."
      },
      "major_infiltrates": {
       "type": "boolean",
       "description": "Multifocal dense infiltrates of mast cells (≥15 MCs in aggregates) in bone marrow or another extracutaneous organ, as assigned by the caller (Valent 2016 Table 1 major). true or false. magent does not read a biopsy."
      },
      "atypical_or_spindle": {
       "type": "boolean",
       "description": ">25% atypical (type I/II) or spindle-shaped mast cells in infiltrates or smears, as assigned by the caller (Valent 2016 Table 1 minor a). true or false. magent does not read slides."
      },
      "associated_myeloid_neoplasm": {
       "type": "boolean",
       "description": "Unrelated myeloid neoplasm present as assigned by the caller (Valent 2016 Table 1: item d is not valid). When true, tryptase_gt_20 does not count as a minor. true or false. magent does not diagnose a myeloid neoplasm."
      }
     }
    }
   }
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/who-2016-systemic-mastocytosis-criteria-calculator-magent-dc49b4ad/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)