def collection_core_fields(item):
    """Extract only fields that are used to identify a record"""
    record = {}
    # Define umm
    umm = item.get('umm', {})
    record['ShortName'] = umm.get('ShortName')
    record['Version'] = umm.get('Version')
    record['EntryTitle'] = umm.get('EntryTitle')
    # Define meta
    meta = item.get('meta', {})
    record['concept-id'] = meta.get('concept-id')
    return {key: value for key, value in record.items() if value}