An action of interest that has happened, can happen, is happening, is intended to happen, or is requested/demanded to happen. An act is an intentional action in the business domain of HL7. Healthcare (and any profession or business) is constituted of intentional actions. An Act instance is a record of such an intentional action.

Any intentional action can exist in different "moods". Moods describe activities as they progress in the business cycle, from defined, through planned and ordered to complete.

Any instance of an Act assumes one and only one mood and will not change its mood along its life cycle. The moods - definition, intent, order, event - seem to specify a life cycle of an activity. However, the participants in the activity in these different moods are different, as is the data. Therefore, the mood of an Act instance is static. The progression actualization (i.e., the progression from defined, through planned and ordered, to being performed) is called the "business cycle" to distinguish it from the "life cycle" of a single act instance. Related Act instances that form such a "business cycle" are linked through the ActRelationship class.

Examples for acts in health care are: a clinical test, an assessment of health condition (such as problems and diagnoses), the setting of healthcare goals, the performance of treatment services (such as medication, surgery, physical and psychological therapy), assisting, monitoring or attending, training and education services to patients and their next of kin, and notary services (such as advanced directives or living will).

Acts have participants, which can be actors or targets. Examples of actors are nurses, doctors, family members, notary publics, and service organizations -- every person or organization that is capable of independent decisions and can thus is responsible (and liable) for the actions performed.

Target participants in an act may include the patient, the patient's spouse, family, or community, a specimen drawn from the patient or from any object of interest. As patients do play active roles in their own healthcare, the patient can be both an active participant and a target participant at the same time (self-administered or reflexive services.)

An act can have multiple active participants and multiple target participants, their specific role being distinguished in the "typeCode" of the respective instance of the Participation class. In particular, an act involving coordination of care may involve two or more active participants -- playing different roles -- who interact on behalf of a patient, family, or aggregate in the role of target participant. For example, a nurse (active participant) calls Meals on Wheels (active participant) on behalf of the patient (target participant).

An act includes the "results", "answers" or informational "procedure products" gained during the act. In this model, "results" do not exist without an act, and every clinical result, including those results gained accidentally, is gleaned via an act. In other moods, such as "definition " or "intent", the results are the possible results, the expected or aimed-for results, or the tested-for results.

An agreement of obligation between two or more parties that is subject to contractual law and enforcement.

A contract whose value is measured in monetary terms.

A health care insurance policy or plan that is contractually binding between two or more parties.

Observations are actions performed in order to determine an answer or result value. Observation result values (Observation.value) include specific information about the observed object. The type and constraints of result values depend on the kind of action performed.

Clinical documents commonly have 'Subjective' and 'Objective' findings, both of which are kinds of Observations. In addition, clinical documents commonly contain 'Assessments', which are also kinds of Observations. Thus, the establishment of a diagnosis is an Observation.

Container for Correlated Observation Sequences sharing a common frame of reference. All Observations of the same cd must be comparable and relative to the common frame of reference. For example, a 3-channel ECG device records a 12-lead ECG in 4 steps (3 leads at a time). Each of the separate 3-channel recordings would be in their own "OBSCOR". And, all 4 OBSCOR would be contained in one OBSSER because all the times are relative to the same origin (beginning of the recording) and all the ECG signals were from a fixed set of electrodes.

Container for Observation Sequences (Observations whose values are contained in LIST<>'s) having values correlated with each other. Each contained Observation Sequence LIST<> must be the same length. Values in the LIST<>'s are correlated based on index. E.g. the values in position 2 in all the LIST<>'s are correlated. This is analogous to a table where each column is an Observation Sequence with a LIST<> of values, and each row in the table is a correlation between the columns. For example, a 12-lead ECG would contain 13 sequences: one sequence for time, and a sequence for each of the 12 leads.

A public health case is an Observation representing a condition or event that has a specific significance for public health. Typically it involves an instance or instances of a reportable infectious disease or other condition. The public health case can include a health-related event concerning a single individual or it may refer to multiple health-related events that are occurrences of the same disease or condition of interest to public health. An outbreak involving multiple individuals may be considered as a type of public health case. A public health case definition (Act.moodCode = "definition") includes the description of the clinical, laboratory, and epidemiologic indicators associated with a disease or condition of interest to public health. There are case definitions for conditions that are reportable, as well as for those that are not. There are also case definitions for outbreaks. A public health case definition is a construct used by public health for the purpose of counting cases, and should not be used as clinical indications for treatment. Examples include AIDS, toxic-shock syndrome, and salmonellosis and their associated indicators that are used to define a case.

An outbreak represents a series of public health cases. The date on which an outbreak starts is the earliest date of onset among the cases assigned to the outbreak, and its ending date is the last date of onset among the cases assigned to the outbreak.

Regions of Interest (ROI) within a subject Act. Primarily used for making secondary observations on a subset of a subject observation. The relationship between a ROI and its referenced Act is specified through an ActRelationship of type "subject" (SUBJ), which must always be present.

A Region of Interest (ROI) specified for a multidimensional observation, such as an Observation Series (OBSSER.) The ROI is specified using a set of observation criteria, each delineating the boundary of the region in one of the dimensions in the multideimensional observation. The relationship between a ROI and its referenced Act is specified through an ActRelationship of type subject (SUBJ), which must always be present. Each of the boundary criteria observations is connected with the ROI using ActRelationships of type "has component" (COMP). In each boundary criterion, the Act.code names the dimension and the Observation.value specifies the range of values inside the region. Typically the to be bounded dimension is continuous, and so the Observation.value will be an interval (IVL) data type. The Observation.value need not be specified if the respective dimension is only named but not constrained. For example, an ROI for the QT interval of a certain beat in EKG Lead II would contain 2 boundary criteria, one naming the interval in time (constrained), and the other naming the interval in ECG Lead II (only named, but not constrained.)

A Region of Interest (ROI) specified for an image using an overlay shape. Typically used to make reference to specific regions in images, e.g., to specify the location of a radiologic finding in an image or to specify the site of a physical finding by "circling" a region in a schematic picture of a human body. The units of the coordinate values are in pixels. The origin is in the upper left hand corner, with positive X values going to the right and positive Y values going down. The relationship between a ROI and its referenced Act is specified through an ActRelationship of type "subject" (SUBJ), which must always be present.

An observation identifying a potential negative occurrence as a result of an Act or combination of Acts.

Observation on a condition at a point in time that includes any observations or procedures associated with that condition as well as links to previous conditions nodes on a related condition

Experience or observable finding persistent over time that tends to require intervention or management; more complex than a simple observation made at a point in time; may exist before an observation or intervention is made; Examples: a health risk, a financial risk, public health risk, pregnancy, health maintenance, illness

Class for holding attributes unique to diagnostic images.

An officially or unofficially instituted program to track acts of a particular type or categorization.

An observation on a specimen in a laboratory environment that may affect processing, analysis or result interpretation

Supply orders and deliveries are simple Acts that focus on the delivered product. The product is associated with the Supply Act via Participation.typeCode="product". With general Supply Acts, the precise identification of the Material (manufacturer, serial numbers, etc.) is important. Most of the detailed information about the Supply should be represented using the Material class. If delivery needs to be scheduled, tracked, and billed separately, one can associate a Transportation Act with the Supply Act. Pharmacy dispense services are represented as Supply Acts, associated with a SubstanceAdministration Act. The SubstanceAdministration class represents the administration of medication, while dispensing is supply.

Diet services are supply services, with some aspects resembling Medication services: the detail of the diet is given as a description of the Material associated via Participation.typeCode="product". Medically relevant diet types may be communicated in the Diet.code attribute using domain ActDietCode, however, the detail of the food supplied and the various combinations of dishes should be communicated as Material instances.

A structure is a container within a document. Structures have captions which can be coded. Structures can nest, and structures can contain entries.

A clinical document is a documentation of clinical observations and services, with the following characteristics: (1) Persistence - A clinical document continues to exist in an unaltered state, for a time period defined by local and regulatory requirements; (2) Stewardship - A clinical document is maintained by a person or organization entrusted with its care; (3) Potential for authentication - A clinical document is an assemblage of information that is intended to be legally authenticated; (4) Wholeness - Authentication of a clinical document applies to the whole and does not apply to portions of the document without the full context of the document; (5) Human readability - A clinical document is human readable."

A clinical document that conforms to Level One of the HL7 Clinical Document Architecture (CDA)

A list of items

Specifies whether a list is "ordered" or "unordered". Use an ordered list when the ordering of list items is meaningful.

A table structure is either a column structure, a row structure, or a table cell.

A cell in a table.

A data cell in a table

A header cell in a table

A table column or column group.

A column in a table

A defined group of columns in a table

A table row

A defined group of rows in a table

Segment types specify table header, table footer, or table body, as defined within the XHTML 4.0 Table Model

Table body, as defined within the XHTML 4.0 Table Model

Table footer, as defined within the XHTML 4.0 Table Model

Table header, as defined within the XHTML 4.0 Table Model

A row in a table

Represents the body of a document on the Clinical Document Architecture standards.

A non-semantic wrapper for plain text in a clinical document

An item in a list

A paragraph in a clinical document

Represents a section in a document on the Clinical Document Architecture standards.

A container consisting of multiple cells arranged in rows and columns.

A link using an HTML anchor tag

An XML attribute used when local semantics have no corresponding representation in the CDA specification

XML markup used when local semantics have no corresponding representation in the CDA specification.

An accommodation is a service provided for a Person or other LivingSubject in which a place is provided for the subject to reside for a period of time. Commonly used to track the provision of ward, private and semi-private accommodations for a patient a

A financial account established to track the net result of financial acts.

A unit of work, a grouper of work items as defined by the system performing that work. Typically some laboratory order fulfillers communicate references to accessions in their communications regarding laboratory orders. Often one or more specimens are related to an accession such that in some environments the accession number is taken as an identifier for a specimen (group).

A transformation process where a requested invoice is transformed into an agreed invoice. Represents the adjudication processing of an invoice (claim). Adjudication results can be adjudicated as submitted, with adjustments or refused.

Adjudication results comprise 2 components: the adjudication processing results and a restated (or adjudicated) invoice or claim

An act representing a system action such as the change of state of another act or the initiation of a query. All control acts represent trigger events in the HL7 context. ControlActs may occur in different moods.

The Consent class represents informed consents and all similar medico-legal transactions between the patient (or his legal guardian) and the provider. Examples are informed consent for surgical procedures, informed consent for clinical trials, advanced beneficiary notice, against medical advice decline from service, release of information agreement, etc.

The details of consents vary. Often an institution has a number of different consent forms for various purposes, including reminding the physician about the topics to mention. Such forms also include patient education material. In electronic medical record communication, consents thus are information-generating acts on their own and need to be managed similar to medical activities. Thus, Consent is modeled as a special class of Act.

The "signatures" to the consent document are represented electronically through Participation instances to the consent object. Typically an informed consent has Participation.typeCode of "performer" (the healthcare provider informing the patient, and "consenter", the patient or legal guardian. Some consent may associate a witness or a notary public (e.g., living wills, advanced directives). In consents where a healthcare provider is not required (e.g. living will), the performer may be the patient himself or a notary public.

Some consent has a minimum required delay between the consent and the service, so as to allow the patient to rethink his decisions. This minimum delay can be expressed in the act definition by the ActRelationship.pauseQuantity attribute that delays the service until the pause time has elapsed after the consent has been completed.

An Act where a container is registered either via an automated sensor, such as a barcode reader, or by manual receipt

An interaction between a patient and healthcare participant(s) for the purpose of providing patient service(s) or assessing the health status of a patient. For example, outpatient visit to multiple departments, home health support (including physical therapy), inpatient hospital stay, emergency room visit, field visit (e.g., traffic accident), office visit, occupational therapy, telephone call.

An event that occurred outside of the control of one or more of the parties involved. Includes the concept of an accident.

The act of transmitting information and understanding about a topic to a subject.

Discussion: This act may be used to request that a patient or provider be informed about an Act, or to indicate that a person was informed about a particular act.

Represents concepts related to invoice processing in health care

WorkingList collects a dynamic list of individual instances of Act via ActRelationship which reflects the need of an individual worker, team of workers, or an organization to manage lists of acts for many different clinical and administrative reasons. Examples of working lists include problem lists, goal lists, allergy lists, and to-do lists.

The term "procedure" is also commonly known as a "surgical procedure" or an "operative procedure". Typically, a surgical procedure involves planned alteration of the structure of the body, ordinarily requiring the disruption of some body surface, usually through an incision.

An introduction of a patient from a source caregiver to a target caregiver or provider institution, typically for the purpose of obtaining the target caregiver's assessment and treatment recommendations. A referral may authorize a specified quantity of a particular kind or level of service. A referral may also simply be a recommendation or introduction.

Represents the act of maintaining information about an entity or role in a registry. The class is most general, designed to support a variety of registries for persons, patients, practitioners, equipment, etc. If required, specific registry types will be treated as specializations of this class.

SubstanceAdministration is an Act using a Material as a therapeutic agent. The effect of the therapeutic substance is typically established on a biochemical basis, however, that is not a requirement. For example, radiotherapy can largely be described in the same way, especially if it is a systemic therapy such as radio-iodine.

A procedure or treatment performed on a specimen to prepare it for analysis

Transportation is the moving of a payload (people or material) from a location of origin to a destination location. Thus, any transport service has the three target instances of type payload, origin, and destination, besides the targets that are generally used for any service (i.e., performer, device, etc.)

A sub-class of Act representing any transaction between two accounts whose value is measured in monetary terms.

In the "intent" mood, communicates a request for a transaction to be initiated, or communicates a transfer of value between two accounts.

In the "event" mood, communicates the posting of a transaction to an account.

A transformation process where a requested invoice is transformed into an agreed invoice. Represents the adjudication processing of an invoice (claim). Adjudication results can be adjudicated as submitted, with adjustments or refused.

Adjudication results comprise 2 components: the adjudication processing results and a restated (or adjudicated) invoice or claim