diff --git a/MD_STD_IN.php b/MD_STD_IN.php
index ff9159a..e7412b7 100644
--- a/MD_STD_IN.php
+++ b/MD_STD_IN.php
@@ -55,7 +55,7 @@ class MD_STD_IN {
             ]
         );
 
-        if ($input === null) {
+        if ($input === false) {
             throw new MDpageParameterNotNumericException("Value is not numeric.");
         }