# Biomarker Longevity Index Calculator

> Biomarker Longevity Index Calculator is a paid API for AI agents from bio.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Standardizes caller-supplied biomarker values against provided reference means and standard deviations, flips markers where lower is better, and computes a weighted composite score mapped to a 0–100 index.

## Facts

- Endpoint: POST https://bio.halowerk.com/v1/biomarker-longevity
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/biomarker-longevity-index-calculator-72d9ac7a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oubKHts94D701In6L7uC7

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 biomarker-longevity-index-calculator-72d9ac7a -d '<json body>'
```

Example prompt: Compute a composite longevity index for these lab results — LDL cholesterol at 110 with a reference mean of 100 and SD of 20 (lower is better, weight 2.0), and fasting glucose at 90 with mean 85, SD 15 (lower is better, weight 1.5) — and give me the final 0–100 score.

## When to prefer this

Choose this endpoint when you need to aggregate multiple biomarkers with caller-defined reference ranges and weights into a single normalized index, especially when the favorable direction varies per marker (some higher is better, some lower). Prefer this over generic statistics APIs when you need the specific z-score normalization, direction-flip, and 0–100 bounded mapping in one step. Not suitable if you need clinically validated scoring systems or diagnosis — use only with caller-supplied reference norms.

## Known failure modes

- Missing required fields (name, value, reference_mean, reference_sd, favorable_direction, weight) returns a validation error
- reference_sd below minimum threshold (1e-12) triggers a validation error
- Array of biomarkers is empty or exceeds 200 items returns a bounds error
- Non-numeric values for numeric fields return a type error
- Weight of zero effectively excludes that marker from the composite
- Extreme outlier values may produce edge scores near 0 or 100

## How this service works

Standardizes each supplied value against its supplied mean and standard deviation, flips markers whose favorable direction is lower, and computes a weighted composite mapped to a bounded 0–100 index. The references and weights come entirely from the caller; this is not a validated longevity score, diagnosis, prognosis or medical advice.

## Output

Returns a bounded 0–100 composite index computed from the caller-supplied biomarkers, along with per-marker standardized scores and their weighted contributions. Not a medical diagnosis, prognosis, or validated longevity score — the result reflects only the references and weights provided by the caller.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "biomarkers": {
   "type": "array",
   "items": {
    "type": "object",
    "required": [
     "name",
     "value",
     "reference_mean",
     "reference_sd",
     "favorable_direction",
     "weight"
    ],
    "properties": {
     "name": {
      "type": "string",
      "maxLength": 128,
      "minLength": 1
     },
     "value": {
      "type": "number",
      "maximum": 1000000000000,
      "minimum": -1000000000000
     },
     "weight": {
      "type": "number",
      "maximum": 1000000,
      "minimum": 0
     },
     "reference_sd": {
      "type": "number",
      "maximum": 1000000000000,
      "minimum": 1e-12
     },
     "reference_mean": {
      "type": "number",
      "maximum": 1000000000000,
      "minimum": -1000000000000
     },
     "favorable_direction": {
      "enum": [
       "higher",
       "lower"
      ],
      "type": "string"
     }
    },
    "additionalProperties": false
   },
   "maxItems": 200,
   "minItems": 1
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/biomarker-longevity-index-calculator-72d9ac7a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from bio.halowerk.com](https://www.zero.xyz/host/bio.halowerk.com/llms.txt)