var start = new ISODate("2015-05-01T00:00:00.001-07").toISOString();
var end = new ISODate("2015-05-31T00:00:00.001-07").toISOString();

var min = 60;
var max = 220;

var bgChecks = db.treatments.find({$and: [
  {created_at: {$gt: start}}
  , {created_at: {$lt: end}}
  , {glucose: {$exists: true}}
  , {glucoseType: 'Finger'}
]});

bgChecks.forEach(function(doc) {
  var bg = Number(doc.glucose);
  if (bg >= min && bg <= max) {
    print(new Date(doc.created_at).getTime() + '\t' +new Date(doc.created_at).toLocaleString() + '\t' + doc.glucose);
  }
});