diff --git a/core/modules/simpletest/simpletest.module b/core/modules/simpletest/simpletest.module
index 847dd6e..ebb1277 100644
--- a/core/modules/simpletest/simpletest.module
+++ b/core/modules/simpletest/simpletest.module
@@ -673,12 +673,12 @@ function simpletest_clean_environment() {
  * Removes prefixed tables from the database from crashed tests.
  */
 function simpletest_clean_database() {
-  $tables = db_find_tables(Database::getConnection()->prefixTables('{test}') . '%');
+  $tables = db_find_tables('test%');
   $count = 0;
   foreach ($tables as $table) {
-    // Strip the prefix and skip tables without digits following "simpletest",
-    // e.g. {simpletest_test_id}.
-    if (preg_match('/test\d+.*/', $table, $matches)) {
+    // Only drop tables which begin wih 'test' followed by digits, for example,
+    // example, {test12345678node__body}.
+    if (preg_match('/^test\d+.*/', $table, $matches)) {
       db_drop_table($matches[0]);
       $count++;
     }