LOINC PrThr values with MCnc example units?

If you do a LOINC search of “Property:PrThr” on this website (with configuration set to at least 1000 results per page), and then you sort by exUCUMUnits, you will find a number of those PrThr codes have example UCUM units that are essentially MCnc (mass over volume) style units. I don’t totally understand the PrThr property, but per the documentation, it doesn’t sound like these should have MCnc style units. Am I missing something?



Thank you for your post. You are correct that these should not have example units. I reviewed the terms with PrThr as the Property and having example UCUM units. The issue occurred with our internal processing and will be fixed in the next release (December). The expected results for PrThr would be ordinal, e.g. Present/Absent, Detected/Not detected, 1+/2+/3+, etc. Such results are based on either a cut-off (threshold) value or the presence of the analyte – hence the Property of “PrThr” or “Presence or Threshold”.




Thanks for your response. I’ve noticed a lot of potentially erroneous ‘example UCUM unit’ fields by using basic SQL queries via UMLS (note that I am using an 2018 version of UMLS, so info may be out of date).

For example, for substance concentration, with the query “SELECT distinct s2.atv FROM mrsat s1, mrsat s2 WHERE (s1.SAB=‘LNC’) AND (s1.ATN=‘LOINC_PROPERTY’) AND (s1.ATV=‘SCnc’) AND (s2.CODE=s1.CODE) AND (s2.SAB=‘LNC’) AND (s2.ATN=‘EXAMPLE_UCUM_UNITS’)”, one of the returned example UCUM units is “umol/mol{creat}”.

When I replace the ‘SCnc’ (substance concentration) with ‘ACnc’ (arbitrary concentration), some of the units I get are ‘mg/dL’ and ‘umol/L’. I’m not sure that these are inappropriate, but I was under the impression that the numerator for ACnc values should be an arbitrary unit.