# Index case^comparison case

**URL:** <https://forum.loinc.org/t/index-case-comparison-case/927>\
**Category:** general-discussion\
**Created:** [February 2, 2017, 4:22am UTC](https://forum.loinc.org/t/index-case-comparison-case/927 "2017-02-02T04:22:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![fhielkema](https://forum.loinc.org/letter_avatar_proxy/v4/letter/f/76d3ee/32.png) [@fhielkema](https://forum.loinc.org/u/fhielkema)\
**Post date:** [February 2, 2017, 4:22am UTC](https://forum.loinc.org/t/index-case-comparison-case/927/1 "2017-02-02T04:22:26Z")

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Dear Daniel and others,

We are unsure how to interpret the system ‘Index case^comparison case’, used in the LOINC-concept 54096-3. The ^ usually denotes a source, e.g. Urine^Patient = urine from patient. But surely the comparison case is not the source of the index case?

If the intended meaning is ‘a sample from the index case compared to a sample from a comparison case’ then we suggest changing the notation to ‘^Index case/^comparison case’. Is that the right interpretation? Where can I request such a change?

Best wishes,

Feikje Hielkema-Raadsveld, Nictiz (NRC Netherlands)

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**Author:** ![system](https://forum.loinc.org/uploads/default/original/1X/dbab97ce9b2987d788a376e254fcaae249f3b672.png) [@system](https://forum.loinc.org/u/system)\
**Post date:** [June 23, 2023, 3:36pm UTC](https://forum.loinc.org/t/index-case-comparison-case/927/2 "2023-06-23T15:36:37Z")

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