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Looking for clarification re: ICD10 (C78.89) with domain_id of 'Measurement'


In doing a recent mapping exercise, my team and I found that ICD10CM code C78.89 (Secondary malignant neoplasm of other digestive organs) (concept_id = 45576340) is associated with a domain_id of ‘Measurement’. This is contrary to what we believe, which is that this code should be domain_id of ‘Condition’. This appears to be the case for several ICD codes of ‘secondary malignancies.’ Could someone clarify (i) if this is an error in the CDM or (ii) why these select ICD10 codes are encoded as measurements? A query and select results that demonstrate this issue can be found below.

Many thanks in advance!


This is a conscious design decision. In ICD10, secondary malignancies mean tumours, secondary to another, primary tumors – meaning metastases. Biologically and clinically, metastasis is not a separate condition, rather a property of another, primary tumor. It is not diagnosed separately and not treated differently to the origin.

Most real-world cancer registries (which are preferable source of truth to ICD10, which is used mostly for claims) keep metastases information like location and extent in key-value paired fields, which makes them more suited for Measurement domain. As such, OMOP CDM’s own Cancer Modifier vocabulary uses Measurement domain for them.

And everything that maps to a Standard Measurement, like C78.89, is also considered a Measurement.

Domain structure of OMOP Vocabularies is not guaranteed to map to similar ideas in other classifications, even if there usually is an alignment – most ICD10 concepts are Conditions, but not all of them, and not all of them have to be.

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