Blood Type / Blood Group Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching blood type / blood group, 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

// Blood Type / Blood Group
// ReDoS-safe | RegexVault — Identity & PII > Biometric & Physical

const bloodTypeBloodGroupRegex = /^(A|B|AB|O)[+-]$/;

function validateBloodTypeBloodGroup(input: string): boolean {
  return bloodTypeBloodGroupRegex.test(input);
}

// Example
console.log(validateBloodTypeBloodGroup("A+")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Biometric & Physical 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

ABO blood groups: A, B, AB, O. Rh factor: + (positive) or - (negative). O- (O negative) is the universal donor for red blood cells. AB+ is the universal recipient. Blood type is health data classified as sensitive under GDPR Article 9.