diff --git a/validation/README.md b/validation/README.md
index 3cab25b..c9981c5 100644
--- a/validation/README.md
+++ b/validation/README.md
@@ -6,7 +6,7 @@ Library containing validator functions
 
 ### isRgbaString
 
-Test if a given string is an RGBA value. You should lowercase the value and remove (or at least trim) all whitespace.
+Test if a given string matches the pattern of an RGBA value.
 
 **Allowed formats**:
 
@@ -16,6 +16,6 @@ Test if a given string is an RGBA value. You should lowercase the value and remo
 ```ts
 import { isRgbaString } from "@nzz/et-utils-validation";
 
-const rgba: String = "RGBA(255 ,255 , 0, 1.0) ".toLowerCase().replace(/ +/g, '');
+const rgba: String = "RGBA(255 ,255 , 0, 1.0) ";
 isRgbaString(rgba); // true
 ```
diff --git a/validation/src/isRgbaString.ts b/validation/src/isRgbaString.ts
index 5e6c2a0..ed07c68 100644
--- a/validation/src/isRgbaString.ts
+++ b/validation/src/isRgbaString.ts
@@ -5,5 +5,5 @@ export const isRgbaString = (rgba: String): boolean => {
   const regex: RegExp =
     /rgba\(\s*(-?\d+|-?\d*\.\d+(?=%))(%?)\s*,\s*(-?\d+|-?\d*\.\d+(?=%))(\2)\s*,\s*(-?\d+|-?\d*\.\d+(?=%))(\2)\s*,\s*(-?\d+|-?\d*.\d+)\s*\)/;
 
-  return regex.test(rgba);
+  return regex.test(rgba.toLowerCase().replace(/ +/g, ""));
 };