Australian Medicare Number Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching australian medicare number, ported and verified for JavaScript. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// Australian Medicare Number
// ReDoS-safe | RegexVault — Identity & PII > Health Identifiers

const australianMedicareNumberRegex = /^([2-6][0-9]{9})(?:\s*([1-9]))?$/;

function validateAustralianMedicareNumber(input: string): boolean {
  return australianMedicareNumberRegex.test(input);
}

// Example
console.log(validateAustralianMedicareNumber("2123456701")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Health Identifiers category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Australian Medicare numbers start with 2-6 (4=concessional). 10-digit number + 1-digit IRN (Individual Reference Number, 1-6, identifies individuals on a family card). Checksum: weighted sum of first 9 digits, compare to 10th. Services Australia assigns and validates.