| Class | Description | 
|---|---|
| AdverseEvent | An incident, near miss, unsafe condition, or untoward occurrence during treatment. | 
| AllergyIntolerance | Allergy or Intolerance (generally: Risk of adverse reaction to a substance) | 
| BodySite | Specific and identified anatomical location | 
| Claim | Claim, Pre-determination or Pre-authorization | 
| Communication | A record of information transmitted from a sender to a receiver | 
| CommunicationRequest | A request for information to be sent to a receiver | 
| Condition | Detailed information about conditions, problems or diagnoses | 
| Coverage | Insurance or medical plan or a payment agreement | 
| Device | Item used in healthcare | 
| DeviceUseStatement | Record of use of a device | 
| DiagnosticReport | A Diagnostic report - a combination of request information, atomic results, images, interpretation, as well as formatted reports | 
| Encounter | An interaction during which services are provided to the patient | 
| FamilyMemberHistory | Information about patient's relatives, relevant for patient | 
| Flag | Key information to flag to healthcare providers | 
| Goal | Describes the intended objective(s) for a patient, group or organization | 
| ImagingStudy | A set of images produced in single study (one or more series of references images) | 
| Immunization | Immunization event information | 
| ImmunizationRecommendation | Guidance or advice relating to an immunization | 
| Location | Details and position information for a physical place | 
| Medication | Definition of a Medication | 
| MedicationAdministration | Administration of medication to a patient | 
| MedicationDispense | Dispensing a medication to a named patient | 
| MedicationRequest | Ordering of medication for patient or group | 
| MedicationStatement | Record of medication being taken by a patient | 
| Observation | Measurements and simple assertions | 
| Organization | A grouping of people or organizations with a common purpose | 
| Patient | Information about an individual or animal receiving health care services | 
| Practitioner | A person with a  formal responsibility in the provisioning of healthcare or related services | 
| Procedure | An action that is being or was performed on a patient | 
| ProcedureRequest | A request for a procedure or diagnostic to be performed | 
| ReferralRequest | A request for referral or transfer of care | 
| RelatedPerson | An person that is related to a patient, but who is not a direct target of care | 
| Specimen | Sample for analysis | 
| Substance | A homogeneous material with a definite composition | 
The QUICK data model uses the QI-Core profiles to provide a physical representation for the data. QUICK provides a logical model that enables knowledge authors to ignore certain details of the FHIR Physical representation, including:
To address the first issue, the QUICK model maps the FHIR base types to CQL primitives, rather than using the FHIR types directly:
| FHIR Type | CQL Type | 
|---|---|
| base64Binary | String | 
| boolean | Boolean | 
| code | String | 
| CodeableConcept | Concept | 
| Coding | Code | 
| date | DateTime | 
| dateTime | DateTime | 
| decimal | Decimal | 
| id | String | 
| instant | DateTime | 
| integer | Integer | 
| markdown | String | 
| oid | String | 
| Period | Interval<DateTime> | 
| positiveInt | Integer | 
| Range | Interval<Quantity> | 
| string | String | 
| time | Time | 
| uri | String | 
To address the second issue, the QUICK model represents FHIR extensions as first-class attributes of the class. To address the third issue, the QUICK model represents FHIR references as direct appearances of the referenced class or classes. NOTE: The third issue is still being worked out, so current QUICK documentation still uses the Reference type to model references.