The neat FHIR-solution to move to closest parent included in GPS

Using SNOMED CT
1

Hi! Some time ago, there was a presentation at an EXPO or BM on using FHIR resources to translate a peripheral SNOMED CT concept into the closest parent in the GPS. I have searched for information on this, but to no avail. However, I am sure I saw this, and I would like to read up on it again and use it.

Does anyone recognise this, and is there any publicly available information? Fingers crossed!

2

Hi @AnnaRossander , an ECL function was developed for this called the “Bottom” operator.

See documentation and explanation here: SNOMED ECL Guide - Top and Bottom

Please note that Snowstorm and the SI Browser do not yet support the Bottom operator. I believe that Ontoserver does.

There is a workaround equivalent expression constraint that is documented in the linked page.

Just let me know if you would like more examples.

3

Please note that this conversion can result in more than one concept being returned if the full meaning of the concept being converted is not covered by a single concept within the target reference set.

For example when converting 1237056009 |Metastatic carcinoma to lower inner quadrant of breast (disorder)| to concepts within the GPS we get:

  • 145501000119108 |Metastatic malignant neoplasm to breast (disorder)|
  • 373080008 |Malignant neoplasm of lower inner quadrant of breast (disorder)|
  • and 254838004 |Carcinoma of breast (disorder)|

The ECL for this would be (workaround version without the Bottom operator):

( >> 1237056009 AND ^787778008) MINUS >(>> 1237056009 AND ^787778008)

And in FHIR as a ValueSet expansion:

Snowstorm FHIR ValueSet-Expand of the ECL above

For the public Snowstorm instance I have used “http://snomed.info/sct/705115006” within the URL to ensure that the Derivatives Edition is selected which has the GPS refset.

4

Thanks @kkewley! Spot on. :100: