diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5af8a926..7594564e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,8 @@ All notable changes to this project will be documented in this file, in reverse
 
 - [#7](https://github.com/webimpress/coding-standard/pull/7) `Commenting\DocComment` - fixes false-positive when new line was required before doc-block
 
+- [#8](https://github.com/webimpress/coding-standard/pull/8) `Formatting\StringClassReference` - fixes checking if string is a valid class name before check if class/interface/trait exists
+
 ## 1.0.0 - 2019-03-07
 
 Initial release.
diff --git a/src/WebimpressCodingStandard/Sniffs/Formatting/StringClassReferenceSniff.php b/src/WebimpressCodingStandard/Sniffs/Formatting/StringClassReferenceSniff.php
index 438fd70f..5186a5d4 100644
--- a/src/WebimpressCodingStandard/Sniffs/Formatting/StringClassReferenceSniff.php
+++ b/src/WebimpressCodingStandard/Sniffs/Formatting/StringClassReferenceSniff.php
@@ -10,10 +10,11 @@
 use function class_exists;
 use function interface_exists;
 use function ltrim;
-use function str_replace;
+use function preg_match;
 use function strpos;
+use function strtr;
+use function substr;
 use function trait_exists;
-use function trim;
 
 use const T_CONSTANT_ENCAPSED_STRING;
 
@@ -37,7 +38,20 @@ public function process(File $phpcsFile, $stackPtr)
             return;
         }
 
-        $name = trim(str_replace(['"', "'"], '', $tokens[$stackPtr]['content']));
+        $name = strtr($tokens[$stackPtr]['content'], [
+            '"' => '',
+            "'" => '',
+            '\\\\' => '\\',
+        ]);
+
+        if (strpos($name, '\\\\') !== false
+            || preg_match('/[^\\a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]/', $name)
+            || substr($name, -1) === '\\'
+            || ltrim($name, '\\') === ''
+        ) {
+            return;
+        }
+
         if (class_exists($name) || interface_exists($name) || trait_exists($name)) {
             $error = 'String "%s" contains class reference, use ::class instead';
             $data = [$name];
diff --git a/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc b/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc
index 2352e41d..4309c667 100644
--- a/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc
+++ b/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc
@@ -11,3 +11,15 @@ $trait = 'WebimpressCodingStandard\Helper\NamespacesTrait';
 
 $nonExistingClass = 'MyNamespace\ClassDoesNotExist';
 $nonSlash = 'DateTime';
+
+$doubleNamespaceSeparator = 'WebimpressCodingStandardTest\\Ruleset';
+$fourBackslashes = 'WebimpressCodingStandardTest\\\\Ruleset';
+$spaceInTheName = 'WebimpressCodingStandardTest Ruleset';
+$newLineInTheName = 'WebimpressCodingStandardTest
+    Ruleset';
+
+$spaceAtTheBeginning = ' WebimpressCodingStandardTest\\Ruleset';
+$spaceAtTheEnd = ' WebimpressCodingStandardTest\\Ruleset ';
+
+$namespaceSeparatorAtTheEnd = 'WebimpressCodingStandardTest\\Ruleset\\';
+$justNamespaceSeparator = '\\';
diff --git a/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc.fixed b/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc.fixed
index 37a86606..63d387cf 100644
--- a/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc.fixed
+++ b/test/Sniffs/Formatting/StringClassReferenceUnitTest.inc.fixed
@@ -11,3 +11,15 @@ $trait = \WebimpressCodingStandard\Helper\NamespacesTrait::class;
 
 $nonExistingClass = 'MyNamespace\ClassDoesNotExist';
 $nonSlash = 'DateTime';
+
+$doubleNamespaceSeparator = \WebimpressCodingStandardTest\Ruleset::class;
+$fourBackslashes = 'WebimpressCodingStandardTest\\\\Ruleset';
+$spaceInTheName = 'WebimpressCodingStandardTest Ruleset';
+$newLineInTheName = 'WebimpressCodingStandardTest
+    Ruleset';
+
+$spaceAtTheBeginning = ' WebimpressCodingStandardTest\\Ruleset';
+$spaceAtTheEnd = ' WebimpressCodingStandardTest\\Ruleset ';
+
+$namespaceSeparatorAtTheEnd = 'WebimpressCodingStandardTest\\Ruleset\\';
+$justNamespaceSeparator = '\\';
diff --git a/test/Sniffs/Formatting/StringClassReferenceUnitTest.php b/test/Sniffs/Formatting/StringClassReferenceUnitTest.php
index 12620979..5621e666 100644
--- a/test/Sniffs/Formatting/StringClassReferenceUnitTest.php
+++ b/test/Sniffs/Formatting/StringClassReferenceUnitTest.php
@@ -16,6 +16,7 @@ protected function getErrorList(string $testFile = '') : array
             7 => 1,
             8 => 1,
             10 => 1,
+            15 => 1,
         ];
     }