Index: t3lib/db/class.t3lib_db_PreparedStatement.php
===================================================================
--- t3lib/db/class.t3lib_db_PreparedStatement.php	(revision 8623)
+++ t3lib/db/class.t3lib_db_PreparedStatement.php	(working copy)
@@ -397,9 +397,9 @@
 	protected function guessValueType($value) {
 		if (is_bool($value)) {
 			$type = self::PARAM_BOOL;
-		} elseif (t3lib_div::testInt($value)) {
+		} elseif (is_int($value)) {
 			$type = self::PARAM_INT;
-		} elseif (is_null($value) || strtoupper($value) === 'NULL') {
+		} elseif (is_null($value)) {
 			$type = self::PARAM_NULL;
 		} else {
 			$type = self::PARAM_STR;