regex – Regular expression to match the string representation of non ascii characters \u0000-\u007F from a string and replace with empty string in C#?

I am getting hexadecimal representation of unicode characters in my string and want to replace that with empty string. More specifically, trying to match all values within \u0000-\u007F in a string using regex to replace it with empty string with C#.

Example 1:

InputString: “\u007FTestString”

ExpectedResult: TestString

Example 2:

InputString: “\u007FTestString\U0000”

ExpectedResult: TestString

My current solution does

            if (!string.IsNullOrWhiteSpace(testString))
            {
                return Regex.Replace(testString, @"[^\u0000-\u007F]", string.Empty);
            }

does not match the hexadecimal representation of the non-ascii character. How do i get it to match the \u0000-\u007F in the string ?

Any help is appreciated. Thank you!