ForHosting KIT · Developer Utilities

FIB-4 liver fibrosis calculator

The FIB-4 liver fibrosis calculator combines four routinely available values—age, aspartate aminotransferase, alanine aminotransferase, and platelet count—to produce a reproducible fibrosis risk index.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Enter age in years, AST and ALT in units per litre, and platelets in billions per litre. The result includes the calculated score, the conventional low, indeterminate, or high band, the exact formula, and all units needed for an auditable workflow. The calculation is deterministic and runs without a network, model, random value, or clock. It is useful for education and structured screening workflows, but it does not establish a diagnosis or replace interpretation by a qualified clinician. The browser version is free; API automation costs $0.002 per successful item.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

What is the FIB-4 formula?

FIB-4 equals age in years multiplied by AST in U/L, divided by platelet count in 10^9/L multiplied by the square root of ALT in U/L.

Which fields are required?

Age, AST, ALT, and platelet_count are all required. Missing, blank, non-numeric, zero, negative, or out-of-range values return invalid_input.

How are the categories assigned?

Scores below 1.3 are labelled low, scores from 1.3 through 2.67 are indeterminate, and scores above 2.67 are high. These are general screening bands, not diagnoses.

What platelet unit should I enter?

Enter platelet count in 10^9/L, commonly shown as billions per litre. A displayed value of 180 should be entered as 180, not 180000.

Does a FIB-4 result diagnose liver fibrosis?

No. FIB-4 is a screening index. Thresholds and performance depend on age, population, condition, and guideline, so clinical interpretation and follow-up belong with a qualified professional.

What does the calculator cost?

The browser calculator is free. Each successful API item costs $0.002; requests rejected during validation are not charged.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/health/fib4

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/health/fib4 \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"age":52,"ast":40,"alt":35,"platelet_count":180}'

const res = await fetch("https://api.kit.forhosting.com/health/fib4", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "age": 52,
    "ast": 40,
    "alt": 35,
    "platelet_count": 180
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/fib4",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "age": 52,
    "ast": 40,
    "alt": 35,
    "platelet_count": 180
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/fib4", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"age":52,"ast":40,"alt":35,"platelet_count":180}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"age":52,"ast":40,"alt":35,"platelet_count":180}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/fib4", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "age": 52,
  "ast": 40,
  "alt": 35,
  "platelet_count": 180
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.fib4",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →