diff --git a/wp-includes/comment-functions.php b/wp-includes/comment-functions.php
index 7bbbaacf1..8b9c30e5a 100644
--- a/wp-includes/comment-functions.php
+++ b/wp-includes/comment-functions.php
@@ -543,20 +543,20 @@ function pings_open() {
 // Non-template functions
 
 function get_lastcommentmodified($timezone = 'server') {
-	global $tablecomments, $cache_lastcommentmodified, $pagenow, $wpdb;
+	global $cache_lastcommentmodified, $pagenow, $wpdb;
 	$add_seconds_blog = get_settings('gmt_offset') * 3600;
 	$add_seconds_server = date('Z');
 	$now = current_time('mysql', 1);
 	if ( !isset($cache_lastcommentmodified[$timezone]) ) {
 		switch(strtolower($timezone)) {
 			case 'gmt':
-				$lastcommentmodified = $wpdb->get_var("SELECT comment_date_gmt FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				$lastcommentmodified = $wpdb->get_var("SELECT comment_date_gmt FROM $wpdb->comments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
 				break;
 			case 'blog':
-				$lastcommentmodified = $wpdb->get_var("SELECT comment_date FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				$lastcommentmodified = $wpdb->get_var("SELECT comment_date FROM $wpdb->comments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
 				break;
 			case 'server':
-				$lastcommentmodified = $wpdb->get_var("SELECT DATE_ADD(comment_date_gmt, INTERVAL '$add_seconds_server' SECOND) FROM $tablecomments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
+				$lastcommentmodified = $wpdb->get_var("SELECT DATE_ADD(comment_date_gmt, INTERVAL '$add_seconds_server' SECOND) FROM $wpdb->comments WHERE comment_date_gmt <= '$now' ORDER BY comment_date_gmt DESC LIMIT 1");
 				break;
 		}
 		$cache_lastcommentmodified[$timezone] = $lastcommentmodified;