Observation Definition

Summary

ObservationDefinition is used to define the structure and expectations of a clinical observation or lab result, such as "Hemoglobin level" or "Blood glucose." These definitions describe the unit, valid value range, data type, and measurement method — forming a template for the actual Observation instances recorded during diagnostics.

In CARE, this ensures consistency across lab results and helps maintain standards for how observations are displayed, interpreted, and validated.

Core Relationships

Related Resource	Purpose
ActivityDefinition	Links expected observations for a test
Observation	Actual instance of a result captured using this definition
SpecimenDefinition	May define specimen type required for this observation

Supported Fields

Field Name	Description	Example
title	Human-readable name of the observation	Hemoglobin
slug	Unique internal reference name	hb-level
description	Clinical context or explanation	"Hemoglobin concentration in blood"
status	Lifecycle status (draft, active, etc.)	active
category	Clinical category	laboratory
data_type	Type of result value	string
Loinc_Code	LOINC or internal code	"LOINCCode"
Body Site	Location on the body for sample collection	"Right Arm"
Method	Measurement technique (e.g., Spectrophotometry)	"Automatic"
unit	Measurement unit	"mmHg"
Components	To record multiple related values	CBC

Functional Workflow

1. Admin defines the observation format for a test (e.g., Hemoglobin).
2. Links this definition to the appropriate ActivityDefinition.
3. When test results are recorded, the system:
   • Enforces data type (e.g., Quantity)
   • Validates result range
   • Uses the preferred_report_name for display