ForHosting KIT · Developer Utilities

Sodium change calculator

The Adrogué-Madias formula estimates how much serum sodium is expected to rise or fall after one litre of a given intravenous fluid.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Clinicians, students, and health-software teams use that estimate when teaching hypotonic and hypertonic infusions, reviewing hyponatremia and hypernatremia cases, or wiring educational calculators into apps. This sodium change calculator takes current serum sodium, infusate sodium concentration, and total body water, then returns the expected change in milliequivalents per litre together with a projected sodium after that litre. Total body water of zero is rejected as invalid_input because a body-water compartment of nothing is not a valid clinical input. The same pure JavaScript module powers the free browser widget and the prepaid API at $0.002 per successful item. Results are educational estimates only and do not replace serial laboratory monitoring, fluid choice, or professional medical advice.

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

How is the expected sodium change calculated?

sodium_change = (infusate_sodium − sodium) / (total_body_water + 1), all in mEq/L with TBW in litres. That is the Adrogué-Madias change per litre of infusate. The response also returns projected_sodium = sodium + sodium_change.

What fields are required?

Three required fields: sodium (current serum Na in mEq/L), infusate_sodium (infusate Na in mEq/L), and total_body_water (litres, must be greater than zero). Missing fields return invalid_input and are not billed.

What happens if total body water is zero?

The request fails with invalid_input. A total body water of zero is not a valid clinical input for this formula and is not charged.

What does the sodium change calculator cost?

The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.

Does this replace medical advice or include potassium in the bag?

No. Results are educational estimates. Potassium is not added unless you already include it in infusate_sodium. People with sodium disorders should follow professional guidance, not this calculator alone.

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/sodium-change

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/sodium-change \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"items":["valor-1","valor-2"]}'

const res = await fetch("https://api.kit.forhosting.com/health/sodium-change", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "items": [
      "valor-1",
      "valor-2"
    ]
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/sodium-change",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "items": [
        "valor-1",
        "valor-2"
    ]
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/sodium-change", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"items":["valor-1","valor-2"]}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"items":["valor-1","valor-2"]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/sodium-change", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "items": [
    "valor-1",
    "valor-2"
  ]
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.sodium_change",
  "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 →