An assay module can define a custom domain to replace LabKey's built-in default assay domains, by adding a schema definition in the domains/ directory. For example:

assay/<assay-name>/domains/<domain-name>.xml

The name of the assay is taken from the <assay-name> directory. The contents of <domain-name>.xml file contains the domain definition and conforms to the <domain> element from assayProvider.xsd, which is in turn a DomainDescriptorType from the expTypes.xsd XML schema. There are three built-in domains for assays: "batch", "run", and "result". This following result domain replaces the build-in result domain for assays:

result.xml

<ap:domain xmlns:exp="http://cpas.fhcrc.org/exp/xml"
            xmlns:ap="http://labkey.org/study/assay/xml">
   <exp:Description>This is my data domain.</exp:Description>
   <exp:PropertyDescriptor>
     <exp:Name>SampleId</exp:Name>
     <exp:Description>The Sample Id</exp:Description>
     <exp:Required>true</exp:Required>
     <exp:RangeURI>http://www.w3.org/2001/XMLSchema#string</exp:RangeURI>
     <exp:Label>Sample Id</exp:Label>
   </exp:PropertyDescriptor>
   <exp:PropertyDescriptor>
     <exp:Name>TimePoint</exp:Name>
     <exp:Required>true</exp:Required>
     <exp:RangeURI>http://www.w3.org/2001/XMLSchema#dateTime</exp:RangeURI>
   </exp:PropertyDescriptor>
   <exp:PropertyDescriptor>
     <exp:Name>DoubleData</exp:Name>
     <exp:RangeURI>http://www.w3.org/2001/XMLSchema#double</exp:RangeURI>
   </exp:PropertyDescriptor>
 </ap:domain>

To deploy the module, the assay directory is zipped up as a <module-name>.module file and copied to the LabKey server's modules directory.

When you create a new assay design for that assay type, it will use the fields defined in the XML domain as a template for the corresponding domain. Changes to the domains in the XML files will not affect existing assay designs that have already been created.