Query: What was my last known 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': '2069-3', 'display': 'Chloride [Moles/volume] in Blood'}], 'text': 'Chloride [Moles/volume] in Blood'}, 'subject': {'reference': 'urn:uuid:152488e2-85f6-45f7-dbfe-b1b77742b4f7'}, 'effectiveDateTime': '2020-10-01T06:13:35+05:30', 'valueQuantity': {'value': 101.69, 'unit': 'mmol/L', 'system': 'http://unitsofmeasure.org', 'code': 'mmol/L'}, 'interpretation': None}