diff --git a/check_json.pl b/check_json.pl
index fb253c9..63d6a9e 100755
--- a/check_json.pl
+++ b/check_json.pl
@@ -218,7 +218,9 @@ if ($np->opts->perfvars) {
         # make label ascii compatible
         $label =~ s/[^a-zA-Z0-9_-]//g  ;
         my $perf_value;
-        $perf_value = $json_response->{$key};
+        my $perf_value_str = '$perf_value = $json_response->'.$key;
+        if ($np->opts->verbose) { (print Dumper ($perf_value_str))};
+        eval $perf_value_str;
         if ($np->opts->verbose) { print Dumper ("JSON key: ".$label.", JSON val: " . $perf_value) };
         if ( defined($perf_value) ) {
             # add threshold if attribute option matches key
@@ -248,7 +250,9 @@ if ($np->opts->outputvars) {
         # make label ascii compatible
         $label =~ s/[^a-zA-Z0-9_-]//g;
         my $output_value;
-        $output_value = $json_response->{$key};
+        my $output_value_str = '$output_value = $json_response->'.$key;
+        if ($np->opts->verbose) { (print Dumper ($output_value_str))};
+        eval $output_value_str;
         push(@statusmsg, "$label: $output_value");
     }
 }