ISREF

The value to test for reference type. For example: A1, B2:D5, a named range, or any expression that might be a reference.

ISREF tests whether a value is a cell or range reference (like A1, B2:D5, or named ranges). It returns TRUE for valid references and FALSE for literal values like numbers, text, logical values, or errors. This function is particularly useful in complex formulas where you need to determine if an argument is a reference or a direct value.