Realname is not computed

Is there anyone out there having issues populating Realname from the nodes?

When I output the $node with dsm($node); , I see the realname value is there, but is returns an empty value with the code below:

$node_title = $node->title;
$seller     = $node->realname;
$details    = $node->field_desc[0]['value'];
$node_field[0]['value'] = 'Title: ' . $node_title . ' | Seller: ' . $seller . ' | Details: ' . $details;

Any ideas?

Thanks,