diff --git a/src/VaultPHP/Response/MetaData.php b/src/VaultPHP/Response/MetaData.php
index 878c58c..746ffa6 100644
--- a/src/VaultPHP/Response/MetaData.php
+++ b/src/VaultPHP/Response/MetaData.php
@@ -129,7 +129,7 @@ public function containsError($error) {
         foreach ($this->getErrors() as $apiError) {
             /** @var string $errorMessage */
             foreach ($error as $errorMessage) {
-                if (preg_match("#${errorMessage}#i", $apiError)) {
+                if (preg_match("#{$errorMessage}#i", $apiError)) {
                     return true;
                 }
             }