Domains - OHDSI/Vocabulary-v5.0 GitHub Wiki
Domains are OMOP-defined clinical entity categories that are defined for each Concept in the Standardized Vocabulary. A list of all Domains is stored in the DOMAIN table. In the CONCEPT table, the field domain_id of each Concept record determines the Domain the Concept belongs to.
All Standard and Classification Concepts (standard_concept = 'S' or 'C') have a unique Domain, while the non-standard Source Concepts (standard_concept = NULL) can have domain_id entries that represent combinations of domains.
Domain assignments are done using a heuristic, which is different for each vocabulary. Most vocabularies have Concepts in one of few Domains, but some of them, like HCPCS or Read, are very broad. The assignment will follow the following logic:
| Domain | Definition | Potential for misinterpretation / Comments |
|---|---|---|
| Procedure | Activities or processes ordered by, or carried out by, a healthcare provider on the patient with a diagnostic or therapeutic purpose | Procedures with diagnostic purposes intend to have non-categorical or numeric results (ECG, ultrasound) and may be treated as Measurements since Measurements are only possible with carrying out technical procedures (see the Measurement chapter). Some procedures may not be carried out by healthcare professionals, such as bystander CPR, hygiene procedures, etc. |
| Measurement | Measurements, i.e. structured values (numerical or categorical) obtained through systematic and standardized examination or testing of a Person or Person’s sample, such as laboratory tests, vital signs, quantitative findings from pathology reports, etc. Measurements differ from Observations in that they require a standardized test or some other activity to generate a quantitative or qualitative result. The Procedure for obtaining the sample is housed in the PROCEDURE_OCCURRENCE table, though it is unnecessary to create a PROCEDURE_OCCURRENCE record for each measurement if one does not exist in the source data.[DD1] | Most examinations and tests in clinical practice are standardized to a certain extent, but not all of them provide structured results.[AD2] [AD3] E.g. WBC analysis requires taking a blood sample, its processing/storage, putting its small part under the microscope, calculating certain parameters and making interpretation. Another example is taking ECG and making its interpretation. Both are the series of activities with numeric and non-numeric results potentially obtained. Which part is which Domain may be clear, but in most cases medical coding doesn’t allow to capture each piece of information separately, so we end up with concepts that fit the definition of both Domains depending on its usage context. They may be distinguished on whether the result for a given concept might be expected or not. In the same way as the Procedure for obtaining the sample “duplicates” the Measurement result, all other grey zone cases should follow the same pattern: “taking ECG” is a Procedure - “ECG interpretation” is the Measurement, “Echocardiography” is a Procedure, but “Left ventricular stroke volume” is a Measurement. However, it doesn’t resolve the problem when only one concept exists. The survey instruments are in the grey zone (with the Observation Domain), because they’re standardized by the authors, but they often don’t imply examination/testing of the patient directly but asking the standardized list of questions. It’s hard to evaluate how much the process is standardized and the result is structured. The features like presence of numeric scores or categorical systems might be used to distinguish them with Observation. Cancer staging is a result of a structured analysis of tumor characteristics. Currently, in the oncology research model, Cancer modifier vocabulary contains predominantly measurements, irrespective of their semantics. |
| Condition | Events of a Person suggesting the presence of a disease or medical condition stated as a diagnosis, a sign, or a symptom, which is either observed by a Provider or reported by the patient. | The most controversial definition leads to multiple domain changes between Condition / Observation domains. Signs and symptoms and other information from the summary descriptions are interpreted freely since everything may or may not be a sign of the disease. |
| Observation | Any data that cannot be represented by any other domains, such as social and lifestyle facts, medical history, family history, etc. Also includes poorly defined facts about a Person obtained in the context of examination, questioning or a procedure. | Most signs and symptoms are obtained by clinicians in the context of examination, questioning or a procedure, carried out in a standardized way, including the Survey instruments, which causes intersections with Measurements. The choice of the domain between condition and observation may also be caused by the current conventions in pre-/post-coordination and need for the use of value_concept_id. |
| Drug | A Drug is a biochemical substance formulated in such a way that when administered to a Person it will exert a certain biochemical effect on the metabolism. Drugs include prescription and over-the-counter medicines, vaccines, and large-molecule biologic therapies. Radiological devices ingested or applied locally do not count as Drugs. | In general, everything that can be represented in a Drug model (ingredient, form, dose) is considered a drug. Almost everything, except for inert metals, such as Titanium, produces some biochemical effect on the metabolism, even radiological contrasts, ingested or applied locally. Products, derived from blood, are not drugs, because their production could not be standardized (one unit of blood contains 170-250 ml produced from a single donation). |
| Device | The Device domain captures information about a person’s exposure to a foreign physical object or instrument which is used for diagnostic or therapeutic purposes through a mechanism beyond chemical action. Devices include implantable objects (e.g. pacemakers, stents, artificial joints), medical equipment and supplies (e.g. bandages, crutches, syringes), other instruments used in medical procedures (e.g. sutures, defibrillators) and material used in clinical care (e.g. adhesives, body material, dental material, surgical material). | Currently, most drug vocabularies include Devices, such as SPF creams, that are distinguished from the Drugs with help of the regexp library. Simplification of the convention would greatly reduce the amount of work needed to incorporate a drug vocabulary. |
| Specimen | Represents concepts describing biological samples collected from a person for laboratory testing, clinical diagnostics, biobanking, or research purposes. Specimen concepts standardize the nature of the sample (e.g., "Blood specimen", "Tumor tissue specimen", "Saliva sample") and are used to classify biological material consistently within the OMOP Vocabulary. | |
| Visit | Defines the context of healthcare encounters, grouping clinical activities by encounter type. Includes outpatient visits, emergency department encounters, inpatient stays, and more granular units (ICU or observation room). Visits provide a temporal and contextual framework for interpreting other events (Conditions, Procedures, Measurements). | |
| Provider | Represents concepts describing individual human healthcare professionals involved in the delivery of patient care. This includes physicians, nurses, pharmacists, therapists, and other clinical practitioners. Provider concepts capture the role or type of healthcare professional, distinct from Care Site concepts, which represent institutions, facilities, or organizational locations where care is provided. |
However, for some of the categories, the assignment can be ambiguous. For these cases, in the OMOP Standardized Vocabulary we use the following rules:
| Category | Example | Domain |
| Behavioral abnormality | ICD10CM Z72.810 Child and adolescent antisocial behavior | Condition |
| Blood bank product | CPT4 86930 Frozen blood, each unit; freezing (includes preparation) | Device |
| Contrast material for imaging | HCPCS A9581 Injection, gadoxetate disodium, 1 ml | Device |
| Food Supplement | SPL 304fdee6-0290-4717-be3d-b367bec7e411 Ferrous Gluconate | Device |
| Graft (alive or artificial) | HCPCS L8670 Vascular graft material, synthetic, implant | Device |
| Implant (not drug eluding) | HCPCS L8610 Ocular implant | Device |
| Medical supply | HCPCS A4336 Incontinence supply, urethral insert, any type, each | Device |
| Nutrition (enteral) | HCPCS B4152 Enteral formula, nutritionally complete, calorically dense (equal to or greater than 1.5 kcal/ml) with intact nutrients, includes proteins, fats, carbohydrates, vitamins and minerals, may include fiber, administered through an enteral feeding tube, 100 cal… | Device |
| Nutrition (parenteral) | HCPCS B5200 Parenteral nutrition solution: compounded amino acid and carbohydrates with electrolytes, trace elements, and vitamins, including preparation, any strength, stress - branch chain amino acids - premix | Device |
| Prosthesis | HCPCS L6687 Upper extremity addition, frame type socket, below elbow or wrist disarticulation | Device |
| Radioactive material for imaging | HCPCS C1204 Technetium tc 99m tilmanocept, diagnostic, up to 0.5 millicuries | Device |
| Radiological procedure supply, radiopharmaceutical) | HCPCS C2644 Brachytherapy source, cesium-131 chloride solution, per millicurie | Device |
| Animal Drug | SPL 3cc46410-1360-43ba-af4f-fd33c9bc3533 THYROID SOOTHE - chamomilla, iodium, lycopus, nux vom, zingiber spray | Drug |
| Cellular Therapy | RxNorm 1000596 autologous cultured chondrocytes 30000000 CELLS/ML Injectable Solution [Carticel] | Drug |
| Implant (drug eluding) | HCPCS J7311 Fluocinolone acetonide, intravitreal implant | Drug |
| Procedure Drug | HCPSC J2704 Injection, propofol, 10 mg | Drug |
| Cytogenetic study | CPT4 88271 Molecular cytogenetics; DNA probe, each (eg, FISH) | Measurement |
| Cytopathology | CPT4 1012386 Cytopathology smears, cervical or vaginal | Measurement |
| Drug testing | HCPCS G6030 Amitriptyline (Assay of amitriptyline) | Measurement |
| Electrocardiogram | HCPCS G0403 Electrocardiogram, routine ecg with 12 leads; performed as a screening for the initial preventive physical examination with interpretation and report | Measurement |
| Hearing test | CPT4 92563 Hearing test using earphones | Measurement |
| Immunological test procedure | CPT4 95065 Direct nasal mucous membrane test | Measurement |
| Semen analysis | HCPCS G0027 Semen analysis; presence and/or motility of sperm excluding huhner | Measurement |
| Cosmetic | SPL 8491b3d2-1edc-4694-adf7-b9649edb00eb ONWARD CHAPSTICK - lipstick | Observation |
| Evaluation or assessment | HCPCS G8930 Assessment of depression severity at the initial evaluation | Observation |
| Lifestyle choice | ICD10 Z58.7 Exposure to tobacco smoke | Observation |
| Pathology report | HCPCS G9428 Pathology report includes the pt category and a statement on thickness and ulceration and for pt1, mitotic raten | Observation |
| Service without exact procedure | HCPCS H0030 Behavioral health hotline service, HCPCS H2016 Comprehensive community support services, per diem | Observation |
| Visit without procedure | HCPCS S9127 Social work visit, in the home, per diem | Observation |
| Anything called *ectomy | HCPCS S2350 Diskectomy, anterior, with decompression of spinal cord and/or nerve root(s), including osteophytectomy; lumbar, single interspace except some devices having *ectomy in description like HCPCS L8020 Breast prosthesis, mastectomy form | Procedure |
| Anything called *graphy | HCPCS C9733 Non-ophthalmic fluorescent vascular angiography | Procedure |
| Anything called *scopy | HCPCS S2070 Cystourethroscopy, with ureteroscopy and/or pyeloscopy; with endoscopic laser treatment of ureteral calculi (includes ureteral catheterization) | Procedure |
| Attention | ICD10 Z43.5 Attention to Cyctostomy | Procedure |
| Brachytherapy | HCPCS G0458 Low dose rate (ldr) prostate brachytherapy services, composite rate | Procedure |
| Counseling | HCPCS H0005 Alcohol and/or drug services; group counseling by a clinician | Procedure |
| Detoxification | HCPCS H0009 Alcohol and/or drug services; acute detoxification (hospital inpatient) | Procedure |
| Examination | ICD10 Z01.0 Examination of eyes and vision | Procedure |
| Imaging | CPT4 91110 Gastrointestinal tract imaging, intraluminal (eg, capsule endoscopy), esophagus through ileum, with interpretation and report | Procedure |
| Immunotherapy | CPT4 95115 Professional services for allergen immunotherapy not including the provision of allergenic extracts; single injection | Procedure |
| Management | ICD10 Z30.9 Contraceptive management, unspecified | Procedure |
| Monitoring | HCPCS 59050 Fetal monitoring during labor by consulting physician (ie, non-attending physician) with written report; supervision and interpretation | Procedure |
| Physician consult | CPT4 1014276 Pathology consultation during surgery | Procedure |
| Procedure Drug (without exact drug information and no RxNorm mapping) | HCPCS J8498 Antiemetic drug, rectal/suppository, not otherwise specified | Procedure |
| Service with exact procedure | HCPCS H0005 Alcohol and/or drug services; group counseling by a clinician | Procedure |
| Surgical pathology (gross or microscopic) | CPT4 88300 Level I - Surgical pathology, gross examination only | Procedure |
| Visit with exact procedure | HCPCS S9097 Home visit for wound care | Procedure |
- Condition
- Currency
- Device
- Drug
- Ethnicity
- Gender
- Measurement
- Measurement Value
- Measurement Value Operator
- Metadata
- Modifier
- Observation
- Place of Service
- Procedure
- Provider Specialty
- Race
- Relationship
- Revenue Code
- Route of Administration
- Specimen
- Specimen Anatomic Site
- Specimen Disease Status
- Type Concept
- Unit
- Visit
- Combination Domains