This code system http://terminology.hl7.org/CodeSystem/observation-category defines the following codes:

CodeDisplayDefinition
social-history Social HistorySocial History Observations define the patient's occupational, personal (e.g., lifestyle), social, familial, and environmental history and health risk factors that may impact the patient's health.
vital-signs Vital SignsClinical observations measure the body's basic functions such as blood pressure, heart rate, respiratory rate, height, weight, body mass index, head circumference, pulse oximetry, temperature, and body surface area.
imaging ImagingObservations generated by imaging. The scope includes observations regarding plain x-ray, ultrasound, CT, MRI, angiography, echocardiography, and nuclear medicine.
laboratory LaboratoryThe results of observations generated by laboratories. Laboratory results are typically generated by laboratories providing analytic services in areas such as chemistry, hematology, serology, histology, cytology, anatomic pathology (including digital pathology), microbiology, and/or virology. These observations are based on analysis of specimens obtained from the patient and submitted to the laboratory.
procedure ProcedureObservations generated by other procedures. This category includes observations resulting from interventional and non-interventional procedures excluding laboratory and imaging (e.g., cardiology catheterization, endoscopy, electrodiagnostics, etc.). Procedure results are typically generated by a clinician to provide more granular information about component observations made during a procedure. An example would be when a gastroenterologist reports the size of a polyp observed during a colonoscopy.
survey SurveyAssessment tool/survey instrument observations (e.g., Apgar Scores, Montreal Cognitive Assessment (MoCA)).
exam ExamObservations generated by physical exam findings including direct observations made by a clinician and use of simple instruments and the result of simple maneuvers performed directly on the patient's body.
therapy TherapyObservations generated by non-interventional treatment protocols (e.g. occupational, physical, radiation, nutritional and medication therapy)
activity ActivityObservations that measure or record any bodily activity that enhances or maintains physical fitness and overall health and wellness. Not under direct supervision of practitioner such as a physical therapist. (e.g., laps swum, steps, sleep data)
<status value="draft"/> <experimental value="false"/> <date value="2022-11-04T18:21:49-06:00"/> <publisher value="FHIR Project team"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> </contact> <description value="Observation Category codes."/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/observation-category"/> <content value="complete"/> <concept> <code value="social-history"/> <display value="Social History"/> <definition value="Social History Observations define the patient's occupational, personal (e.g., lifestyle), social, familial, and environmental history and health risk factors that may impact the patient's health."/> </concept> <concept> <code value="vital-signs"/> <display value="Vital Signs"/> <definition value="Clinical observations measure the body's basic functions such as blood pressure, heart rate, respiratory rate, height, weight, body mass index, head circumference, pulse oximetry, temperature, and body surface area."/> </concept> <concept> <code value="imaging"/> <display value="Imaging"/> <definition value="Observations generated by imaging. The scope includes observations regarding plain x-ray, ultrasound, CT, MRI, angiography, echocardiography, and nuclear medicine."/> </concept> <concept> <code value="laboratory"/> <display value="Laboratory"/> <definition value="The results of observations generated by laboratories. Laboratory results are typically generated by laboratories providing analytic services in areas such as chemistry, hematology, serology, histology, cytology, anatomic pathology (including digital pathology), microbiology, and/or virology. These observations are based on analysis of specimens obtained from the patient and submitted to the laboratory."/> </concept> <concept> <code value="procedure"/> <display value="Procedure"/> <definition value="Observations generated by other procedures. This category includes observations resulting from interventional and non-interventional procedures excluding laboratory and imaging (e.g., cardiology catheterization, endoscopy, electrodiagnostics, etc.). Procedure results are typically generated by a clinician to provide more granular information about component observations made during a procedure. An example would be when a gastroenterologist reports the size of a polyp observed during a colonoscopy."/> </concept> <concept> <code value="survey"/> <display value="Survey"/> <definition value="Assessment tool/survey instrument observations (e.g., Apgar Scores, Montreal Cognitive Assessment (MoCA))."/> </concept> <concept> <code value="exam"/> <display value="Exam"/> <definition value="Observations generated by physical exam findings including direct observations made by a clinician and use of simple instruments and the result of simple maneuvers performed directly on the patient's body."/> </concept> <concept> <code value="therapy"/> <display value="Therapy"/> <definition value="Observations generated by non-interventional treatment protocols (e.g. occupational, physical, radiation, nutritional and medication therapy)"/> </concept> <concept> <code value="activity"/> <display value="Activity"/> <definition value="Observations that measure or record any bodily activity that enhances or maintains physical fitness and overall health and wellness. Not under direct supervision of practitioner such as a physical therapist. (e.g., laps swum, steps, sleep data)"/> </concept> </CodeSystem>