Observations are a central element in healthcare, used to support diagnosis, monitor progress, determine baselines and patterns and even capture demographic characteristics. Most observations are simple name/value pair assertions with some metadata, but some observations group other observations together logically, or even are multi-component observations. Note that the DiagnosticReport resource provides a clinical or workflow context for a set of observations and the Observation resource is referenced by DiagnosticReport to represent laboratory, imaging, and other clinical and diagnostic data to form a complete report.

Uses for the Observation resource include:

• Vital signs such as body weight, blood pressure, and temperature
• Laboratory Data such as blood glucose, or an estimated GFR
• Imaging results of a quantative nature such as bone density or fetal measurements
• Clinical Findings such as abdominal tenderness
• Device measurements such as EKG data or Pulse Oximetry data
• Clinical assessment tools such as APGAR or a Glasgow Coma Score
• Personal characteristics: such as eye-color
• Social history including tobacco use, family support, or cognitive status
• Core characteristics like pregnancy status, or a death assertion

There are three US Core Implementation Guide profiles for this resource:
Laboratory Results
Vital Signs
Smoking Status