how to use "retweeted" field to check if tweet is retweeted

Question

i pulled the tweets from timeline but it also show the retweeted tweets which starts with "RT @" how can i use "retweeted" field to check the tweet. if it was retweeted i will not print it. how can i use it in the code you see :

$url = "https://api.twitter.com/1.1/statuses/home_timeline.json";
$requestMethod = "GET";

if (isset($_GET['user'])){
    $user = $_GET['user'];
} else {
    $user = "Parsi_Tweet";
}

if (isset($_GET['count'])) {
    $count = $_GET['count'];
} else {
    $retweeted_status = "";
}

$getfield = "?screen_name=$user&count=$count";
$twitter = new TwitterAPIExchange($settings);
$string = json_decode($twitter->setGetfield($getfield)
    ->buildOauth($url, $requestMethod)
    ->performRequest(),$assoc = TRUE
);

echo "TIME : ".$items['created_at']."<br />";
echo "TWEET : ". $items['text']."<br />";
echo "BY : ". $items['user']['name']."<br />";