[{"quoteId":1,"screening":{"101":1,"201":1,"301":1,"100":1,"200":1,"300":1,"111":1,"211":1,"311":1}},{"quoteId":2,"screening":{"101":1,"201":1,"301":1,"100":1,"200":1,"300":1,"111":1,"211":2,"311":1}},{"quoteId":3,"screening":{"401":1}}]

db.collection.aggregate([{$set:{screenings:{$filter:{input:{"$objectToArray":"$screening"},cond:{"$regexMatch":{input:"$$this.k",regex:"^(1|2|3)"}}}}}},{$match:{screenings:{$ne:[]}}},{$unset:"screenings"}])