PD-L1 TC vs. IC

Dear all,

we use the code LP 221212-6 Cells.programmed cell death ligand 1 to capture " PD-L1" vlaues in free text. In clinical notes, we found textual examples like

“PD-L1 tumor cell (TC) staining: LOW POSITIVE, PD-K1 immune cell (IC) staining: POSITIVE”

I wonder whether LOINC makes a distinction between TC staining and IC staining, are there 2 different codes available?

All the best
Philipp

Hello Philipp,

Please examine other components that use ‘by clone’ in the component name along with PD-L1. These include Programmed cell death ligand 1 by clone 22C3 and Programmed cell death ligand 1 by clone 28-8. There are a variety of them. Are you able to have a value set of the variety to tie to PD-L1 tumor cell (TC)? Groups in LOINC follow full LOINC terms and not the LOINC Parts (as far as I am aware), so LOINC Groups may not assist you.

Just thinking aloud, but hope this helps get you started,

Pam

Hi Pam, hi all,

first, thanks a lot for your feedback!

I was checking all the “by clone” components. All of them have “Immune Stain” as a Method, so I wonder whether there is a different method such as “tumor (cell) staining” and other than “immune staining” at all? In other words, I don’t know whether especially the first expression in the phrase “PD-L1 tumor cell (TC) staining: LOW POSITIVE, PD-K1 immune cell (IC) staining: POSITIVE” is covered by any loinc code at all?

All the best
Philipp

Hi Philipp,

Let’s first consider the source of the cells being addressed: they can be somatic (of the body naturally) or germline (of a tumor in the body). The component LOINC Part LP221212-6 has a description that appears to read as it is the naturally occuring marker in humans. The Part is also used in LOINC 83053-9 which has a denominator of per 100 tumor cells.

It is a coincidence in this situation that “immune” is a word also used in the staining method. This is a very common staining method of binding to target cells by an immune binding. This is not the same connotation as being a cell of the immune system.

If your systems have chosen to use LOINC Parts for tracking/mining, I would ask if the local design has taken into account the LOINC design of Components (and that multiple LOINC Parts can be linked to become one Component)? My earlier post of finding the “by clone” Components would be suitable for identifying tumor cell lineage, but it may not suit how the laboratory is actually structuring laboratory results. They may run a variety of those clones on a patient sample, and “roll up” the individual results into a single output. Are all of the “…” phrase you mentioned actually in ONE lab value? Are you gleaning from HL7 messages, or are you gathering from an EHR note?

The source of the messages may dictate how LOINC is used locally and answer your question if there is any LOINC code at all.

Best regards,

Pam

Hi Pam,

again, thanks a lot.

The phrase "PD-L1 tumor cell (TC) staining: LOW POSITIVE, PD-K1 immune cell (IC) staining: POSITIVE” is part of an EHR note and the expectation is to map that to TWO different lab values.

My lay expectation would be that LOINC distinguishes between PD-L1 measured in tumor cells vs. in immune cells. Is the system axis of LOINC there to represent the “system”, in this case tumor/immune cell?

All the best
Philipp

Hi Philipp,

I want to clarify several issues in addition to the information Pam provided -

  1. LOINC Parts should not be used to represent lab tests or lab test results. The Parts together define a single LOINC term, so for example, there are several different Parts related to PD-L1, including LP221212-6, that, in various combinations with other Parts, result in 9 different LOINC terms (https://search.loinc.org/searchLOINC/search.zul?query=programmed+ligand+1) that represent various lab tests. Some of those terms have an ordinal scale, meaning they would be used to represent tests that have positive/negative results, but they all specify various clones.

  2. In your example: “PD-L1 tumor cell (TC) staining: LOW POSITIVE, PD-K1 immune cell (IC) staining: POSITIVE”, there are 4 pieces of information - two test names (PD-L1 tumor cell (TC) staining and PD-K1 immune cell (IC) staining), and two results (LOW POSITIVE and POSITIVE). The two test names would be candidates for mapping to LOINC codes (not Part codes), and the two results would be mapped either to SNOMED CT codes (preferred) or LOINC Answer (LA) codes.

Unfortunately we don’t have generic PD-L1 codes that don’t specify the clones, so you would either have to get more information about the specific testing being reported, or potentially request new generic LOINC codes.

  1. As documented in the LOINC terms of use, LOINC Part (LP) codes are non-semantic identifiers and can only be used to organize LOINC terms or link to other ontologies. They should not be used as a stand-alone terminology. Here is the text from Section 5 of the license:

The LOINC parts and LOINC part hierarchies shall not be used in any manner except as they are presented in the Licensed Materials (and/or in other formats of distribution approved by Regenstrief Institute, Inc.) to organize, categorize, and be constituents of LOINC terms, and provide links to external terminologies. The LOINC parts and LOINC part hierarchies are subject to change, addition, modification, or deletion, without notice, and are not strictly managed under the same policies as LOINC terms.

Thanks,
Swapna

Hi Swapna,

thanks a lot for your additional explanations. I’d like to request two new generic LOINC code. Unfortunately, I never requested one before and struggle a bit to fill out the “Requested Terms” sheet. Could you help me with that? My idea would be to have:

  • Component: PD-L1 (generic, not a specific clone)
  • Property: Find (?)
  • Time: Pt (?)
  • System: Tumor cells
  • Scale: qualitative (?)
  • Method: Immune stain
  • Component: PD-L1 (generic, not a specific clone)
  • Property: Find (?)
  • Time: Pt (?)
  • System: Immune Cells
  • Scale: qualitative (?)
  • Method: Immune stain

I imagine this is not entirely correct, so I would be pleased if you could help me requesting the right codes.
Thanks and all the best
Philipp

Hi Philipp,

Please submit a request using the values you have in your message above, and we will work with you to make sure the terms are modeled correctly. Don’t worry about having all of the pieces correct in your initial submission, and it will be easier to work out the details through our submissions process rather than through Forum posts.

The most important thing we need with the submission is de-identified lab reports or clinical notes as you mentioned in your original email, or any other information you can provide about the types of results that you need new LOINC terms for.

Thanks,
Swapna