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how to handle confirmatory tests in lab
New variable --REPNUM
Hi Deepika,
SDTM 3.3 (SDTM IG 3.3) introduced a new variable --REPNUM:
| Variable Name | Variable Label | Type | Role | Description |
| --REPNUM | Repetition Number | Num | Record Qualifier | The instance number of a test that is repeated within a given timeframe for the same test. The level of granularity can vary (e.g., within a time point or within a visit). For example, multiple measurements of blood pressure or multiple analyses of a sample. |
https://www.cdisc.org/standards/foundational/sdtm/sdtm-v1-7
In older versions there are several options:
1. Create LBREPNUM variable in SUPPLB and use it a Key Variable
2. Use LBSPID variable in the same way as --REPNUM. Document your approach well in Define.xml and Reviewer's Guide
Kind Regards,
Sergiy
how to handle confirmatory tests in lab
As an addition to Sergiy's answer, I would prefer the second approach (LBSPID) for older versions of SDTM, as one cannot, in the machine-readable define.xml, document a supplemental qualifier as a key variable (using the KeySquence attribute on ItemRef). Using LBREPNUM as a supplemental qualifier in SUPPLB could lead to serious problems when the submission is loaded into a relational database: when the keys from the define.xml are used to generate the primary key of the table (that is what they are for), then the table loader would report an error for duplicate records and stop loading. IMO, "banning" supplemental qualifier variables to different (SUPPxx) tables was a major design error of SDTM.
So, the better approach is indeed to use LBSPID, but then do not forget to mark it as a key variable in the define.xml using the KeySequence attribute on ItemRef. Also important is that you assign the correct key order (by the numeric value of @KeySequence) in the define.xml.
Jozef Aerts - Define.xml development team
supplemental qualifier keys
Actually, in the Value Level Metadata you can define a supplemental qualifier as a key variable (using the KeySquence attribute on ItemRef).
Of course, the loading application needs to know how to deal with this.
The latest Define-XML v2 stylesheet (2018-11-21, https://wiki.cdisc.org/display/PUB/Stylesheet+Library) also supports this.
Lex Jansen - Define.xml development team
Hi,
How do folks handle a confirmatory lab test result done on the same sample - there are 2 records for same LBTESTCD/VISIT with 2 different LBORRES. Any suggestions?