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The clinical trials data collection process includes standardized practices for managing incomplete subject data. Most subject data is gathered through interactions with health care professionals though some is entered directly by humans subjects. HL7 has developed a standard set of NullFlavor codes represented in an ISO 21090 enumeration. Clinical study records extracted directly from healthcare records may encounter this coding. NullFlavor values are indicated in ODM Clinical Data through the use of a NullFlavor Annotation. A NullFlavor Annotation is an ODM Annotation element with a Flag child element with a codelist reference. The referenced codelist defines the set of NullFlavor values supported for the study. The Annotation element can be used at any level in the ODM clinical data hierarchy. For ODM V2, it means that it can be used with the StudyEventData, ItemGroupData or ItemData elements. For studies that support collection of NullFlavor information, the ODM MetaDataVersion must include a CodeList element to identify the set of NullFlavor values that are allowed. For the use case where the study data will be sourced by electronic health records using FHIR resources, NullFlavor values will be taken from the HL7 Version 3 NullFlavor Value Set or a defining value subset. When the value of a variable cannot be collected, the ItemData element will have the IsNull attribute set to "Yes" and an Annotation child element that provides the applicable NullValue Code. When a StudyEvent identified in a data request or study workflow does not occur, a NullValue Annotation will be provided as a child element of the StudyEventData element. If a Form/Data Collection Instrument is skipped or has no values entered, the NullValue Annotation is provided as a child element of the ItemGroupData element. http://build.fhir.org/ig/HL7/fhir-shorthand/reference.html#defining-value-sets |
Examples
Example 1 Support for a pre-specified set of null flavors
The study metadata includes two CodeList elements with the list of support null flavor values. The first CodeList, Name="NullFlavorValueSubset" is the one referenced in the rest of the code blocks on this page. The second CodeList, Name="NullFlavorValueSubset2" is provided to illustrate a specific definition of the HL7 Null Flavor code "MSK" for a Blinded study.
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In the ODM ClinicalData element, ItemData elements where IsNull is "Yes" include an Annotation element with a Flag element with the CodeListOID attribute set to "STUDY.CL.NullReasonCodelist", the OID of the NullFlavorValueSet codelist.
The Annotation element appears following the AuditRecord element.
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<ClinicalData StudyOID="ODMV2.NF.EX1.Study" MetaDataVersonOID="ODMV2.NF.EX1.MDV">
<SubjectData SubjectKey="001" TransactionType="Insert">
<StudyEventData StudyEventOID="vstBASE">
<ItemGroupData ItemGroupOID="sfrmDM">
<ItemData ItemOID="svarFHMarriage" IsNull="Yes">
<AuditRecord>
<UserRef UserOID="system"/>
<LocationRef LocationOID="CDISC"/>
<DateTimeStamp>2008-03-17T19:21:58+00:00</DateTimeStamp>
</AuditRecord>
<Annotation SeqNum="67944">
<Flag><FlagValue CodeListOID="STUDY.CL.NullReasonCodelist">NA</FlagValue></Flag>
</Annotation>
</ItemData>
</ItemGroupData>
</StudyEventData>
<StudyEventData StudyEventOID="vstWEEK1">
<ItemGroupData ItemGroupOID="sfmECG">
<AuditRecord>
<UserRef UserOID="system"/>
<LocationRef LocationOID="CDISC"/>
<DateTimeStamp>2008-03-24T19:21:58+00:00</DateTimeStamp>
</AuditRecord>
<Annotation SeqNum="67944">
<Flag><FlagValue CodeListOID="STUDY.CL.NullReasonCodelist">MSK</FlagValue></Flag>
</Annotation>
</ItemGroupData>
</StudyEventData>
</SubjectData>
</ClinicalData>
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Example 2 Allow any values from HL7 Null Flavor Value Set
The CodeList definition uses an ExternalCodeList element to identify the dictionary and version. The Coding element provides the URI for the HL7 Null Flavor Value Set.
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The Annotation element appears following the AuditRecord element.
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<ClinicalData StudyOID="ODMV2.NF.EX2.Study" MetaDataVersonOID="ODMV2.NF.EX2.MDV">
<SubjectData SubjectKey="002" TransactionType="Insert">
<StudyEventData StudyEventOID="vstWEEK3">
<ItemGroupData ItemGroupOID="sfrmLB-biomarker">
<AuditRecord>
<UserRef UserOID="system"/>
<LocationRef LocationOID="CDISC"/>
<DateTimeStamp>2019-03-17T19:21:58+00:00</DateTimeStamp>
</AuditRecord>
<Annotation SeqNum="67944">
<Flag><FlagValue CodeListOID="STUDY.CL.NullReasonCodelist">NI</FlagValue></Flag>
</Annotation>
</ItemGroupData>
</StudyEventData>
</SubjectData>
</ClinicalData> |
References
| V3 Null Flavor Value Set | https://terminology.hl7.org/2.0.0/ValueSet-v3-NullFlavor |
| FSH for Code Subset Definitions | http://build.fhir.org/ig/HL7/fhir-shorthand/reference.html#defining-value-sets |
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