# Tisdale 2013 QT Prolongation Risk Score Calculator

> Tisdale 2013 QT Prolongation Risk Score Calculator 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).

Computes the Tisdale 2013 risk score for drug-induced QT prolongation and returns a risk band (low/moderate/high) based on nine clinical parameters.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/tisdale
- 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/tisdale-2013-qt-prolongation-risk-score-calculator-f932d654
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_A0S_3zD9hGJO50RUNhgDc

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 tisdale-2013-qt-prolongation-risk-score-calculator-f932d654
```

Example prompt: Calculate the Tisdale 2013 QT prolongation risk score for a 72-year-old female patient who is on a loop diuretic, has a serum potassium of 3.2 mmol/L, an admission QTc of 460 ms, active sepsis, and is currently on 2 QTc-prolonging drugs — no acute MI or heart failure.

## When to prefer this

Use this endpoint when you need a deterministic, published, citable arithmetic computation of the Tisdale 2013 QT prolongation risk score for a hospitalized patient. It is ideal for clinical decision-support agents that need to risk-stratify patients before initiating QTc-prolonging drugs, and when auditability via a published scoring table is required. It does not replace clinical judgment, diagnose TdP, or recommend drug changes.

## Known failure modes

- Missing required query parameters returns a validation error
- Age outside 18–120 range is rejected
- Potassium outside 1.5–8.0 mmol/L is rejected
- QTc outside 200–800 ms is rejected
- qtc_prolonging_drugs count outside 0–20 is rejected
- Payment failure (x402) if USDC balance is insufficient

## How this service works

Tisdale 2013 QT prolongation risk score (Table 5): age ≥68 (1), female (1), loop diuretic (1), potassium ≤3.5 mmol/L (2), admission QTc ≥450 ms (2), acute MI (2), sepsis (3), heart failure (3), one QTc-prolonging drug (3) plus ≥2 drugs (3 stacked; max 21). Returns bands 0-6 / 7-10 / ≥11. Deterministic published arithmetic with citation; not a medical device, not a drug-stop protocol, and not a TdP diagnosis.

## Output

Returns the calculated Tisdale 2013 risk score (integer, maximum 21) and the corresponding risk band: low (0–6), moderate (7–10), or high (≥11), based on the sum of weighted clinical criteria from Table 5 of Tisdale 2013.

## 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": [
      "age",
      "sex",
      "loop_diuretic",
      "potassium_mmol_l",
      "admission_qtc_ms",
      "acute_mi",
      "sepsis",
      "heart_failure",
      "qtc_prolonging_drugs"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (18-120). Age ≥68 scores 1 (Tisdale 2013 Table 5). 67 does not score."
      },
      "sex": {
       "enum": [
        "female",
        "male"
       ],
       "type": "string",
       "description": "female scores 1; male scores 0 (Tisdale 2013 Table 5)."
      },
      "sepsis": {
       "type": "boolean",
       "description": "Sepsis (Tisdale 2013 Table 5). true or false. Scores 3 if true."
      },
      "acute_mi": {
       "type": "boolean",
       "description": "Acute myocardial infarction (Tisdale 2013 Table 5). true or false. Scores 2 if true."
      },
      "heart_failure": {
       "type": "boolean",
       "description": "Left ventricular dysfunction / heart failure (Tisdale 2013 Table 5). true or false. Scores 3 if true."
      },
      "loop_diuretic": {
       "type": "boolean",
       "description": "Loop diuretic (Tisdale 2013 Table 5). true or false. Scores 1 if true."
      },
      "admission_qtc_ms": {
       "type": "number",
       "description": "Admission QTc in milliseconds (200-800). ≥450 scores 2 (Tisdale 2013 Table 5). 450 scores."
      },
      "potassium_mmol_l": {
       "type": "number",
       "description": "Serum potassium in mmol/L (1.5-8.0). ≤3.5 scores 2 (Tisdale 2013 Table 5). 3.5 scores; 3.51 does not."
      },
      "qtc_prolonging_drugs": {
       "type": "integer",
       "description": "Count of QTc-prolonging drugs (integer 0-20). 0 → 0 points; 1 → 3 points; ≥2 → 6 points (Table 5 one-drug and ≥2-drug rows stack)."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "pro
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "path": "/api/calc/tisdale",
  "count": 2,
  "items": [
   {
    "sex": "male",
    "score": 0,
    "formula": "tisdale",
    "citation": {
     "id": "tisdale-2013",
     "doi": "10.1161/CIRCOUTCOMES.113.000152",
     "pmid": "23716032",
     "title": "Development and validation of a risk score to predict QT interval prolongation in hospitalized patients",
     "source": "Circ Cardiovasc Qual Outcomes. 2013;6(4):479-487",
     "authors": "Tisdale JE, Jaynes HA, Kingery JR, et al."
    },
    "age_years": 60,
    "max_score": 21,
    "components": [
     {
      "value": 60,
      "factor": "age_ge_68",
      "points": 0,
      "present": false
     },
     {
      "factor": "female",
      "points": 0,
      "present": false
     },
     {
      "factor": "loop_diuretic",
      "points": 0,
      "present": false
     },
     {
      "value": 4,
      "factor": "potassium_le_3_5",
      "points": 0,
      "present": false
     },
     {
      "value": 400,
      "factor": "admission_qtc_ge_450",
      "points": 0,
      "present": false
     },
     {
      "factor": "acute_mi",
      "points": 0,
      "present": false
     },
     {
      "factor": "sepsis",
      "points": 0,
      "present": false
     },
     {
      "factor": "heart_failure",
      "points": 0,
      "present": false
     },
     {
      "value": 0,
      "factor": "one_qtc_prolonging_drug",
      "points": 0,
      "present": false
     },
     {
      "value": 0,
      "factor": "two_or_more_qtc_prolonging_drugs",
      "points": 0,
      "present": false
     }
    ],
    "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.",
    "tisdale_band": "0-6",
    "admission_qtc_ms": 400,
    "potassium_mmol_l": 4,
    "formula_expression": "Tisdale = age≥68 1 + female 1 + loop_diuretic 1 + potassium≤3.5 2 + admission_QTc≥450 2 + acute_MI 2 + sepsis 3 + heart_failure 3 + one_QTc_prolonging_drug 3 + ≥2_QTc_prolonging_drugs 3; Table 5; max 21; bands 0-6 / 7-10 / ≥11",
    "qtc_prolonging_drugs": 0
   },
   {
    "sex": "male",
    "score": 0,
    "formula": "tisdale",
    "citation": {
     "id": "tisdale-2013",
     "doi": "10.1161/CIRCOUTCOMES.113.000152",
     "pmid": "23716032",
     "title": "Development and validation of a risk score to predict QT interval prolongation in hospitalized patients",
     "sou
… (truncated)
```

## More

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