Query: What was my last recorded body mass index (BMI)?, FHIR Resource: {'resourceType': 'Observation', 'status': 'final', 'category': [{'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/observation-category', 'code': 'laboratory', 'display': 'Laboratory'}]}], 'code': {'coding': [{'system': 'http://loinc.org', 'code': '777-3', 'display': 'Platelets [#/volume] in Blood by Automated count'}], 'text': 'Platelets [#/volume] in Blood by Automated count'}, 'subject': {'reference': 'urn:uuid:ca7c93ba-086d-251a-d6f7-bc385a19b352'}, 'effectiveDateTime': '2014-12-29T09:55:52+05:30', 'valueQuantity': {'value': 181.2, 'unit': '10*3/uL', 'system': 'http://unitsofmeasure.org', 'code': '10*3/uL'}, 'interpretation': None}