$service = new NetSuiteService($this->config);
$custSearchField = new SearchStringField();
$custSearchField->value = new ListOrRecordRef();
$custSearchField->value->internalId = "custrecord_serial_number";
$custSearchField->value->value = $test["serial"];
$search = new CustomRecordSearch();
$search->serial = $custSearchField;
$searchRequest = new searchRequest();
$searchRequest->searchRecord = $search;
$data = $service->search($searchRequest);