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Mapping of LOINC Part components used in susceptibility LOINC terms, specifically the ones that contain more than one antibiotics:

18865-6Ampicillin+SulbactamSuscPtIsolateOrdQn 
20374-5Ampicillin+SulbactamSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria
43251Ampicillin+SulbactamSuscPtIsolateQnMLC
11749Ampicillin+SulbactamSuscPtIsolateOrdQnMIC
12055Ampicillin+SulbactamSuscPtIsolateOrdQnAgar diffusion
1855616Ampicillin+SulbactamSuscPtIsolateOrdQnGradient strip


And the ones that contain strength:

48177-0Streptomycin 1.0 ug/mLSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria
25206-4Streptomycin 10.0 ug/mLSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria
25205-6Streptomycin 2.0 ug/mLSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria
46719-1Streptomycin 4.0 ug/mLSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria
25185-0Streptomycin 6.0 ug/mLSuscPtIsolateOrdQnMethod for Slow-growing mycobacteria


This issue needs to be considered in association with CTP Project - Elaboration document on Susceptibility:
The modelling design (using the deposition observable / flattened format) is as follows:

‘‘Observable entity’ and
‘property type’ some ‘Susceptibility’ and
‘towards’ some <LOINC.component> and
‘technique’ some <LOINC.method> and
‘scale’ some <LOINC.scale>
‘time aspect’ some ‘Single point in time”
‘inheres in’ some ‘Microorganism’ and
'Direct site = 119303007 | Microbial isolate specimen (specimen) |'

In mapping ‘towards’ some <LOINC.component>:

1) We have mapped the LOINC parts containing one antibiotic to the equivalent substance

LP28719-0 1 Gatifloxacin (Mapped to: 116349004 Gatifloxacin (substance))
LP33354-9 1 Daptomycin (Mapped to: 406439009 Daptomycin (substance))

2) For the ones containing multiple substances, see the latest associated guideline for compound substances:

Combined substances added to the Substance hierarchy must meet the following criteria:

  • The physiologic or biologic action of the combination must be enhanced or synergistic
  • Combinations that do not have an enhanced or synergistic effect (e.g. combinations created for convenience) are out of scope.

Examples of combined substances that are in scope include:Ampicillin + sulbactamPiperacillin + tazobactam

Examples:

LP15937-3 1 Ampicillin+Sulbactam (Mapped to: 703744001 | Ampicillin and sulbactam (substance) |. A product concept also exist: 398786001 Product containing ampicillin and sulbactam (medicinal product))

LP29104-4 1 Quinupristin+Dalfopristin (No susbtance concept created yet. Product concept: 324352008 Product containing dalfopristin and quinupristin (medicinal product))

3) LOINC terms with an antibiotic component with strength specified:

LP229026-2 1 COMPONENT Moxifloxacin 0.5 ug/mL
LP229027-0 1 COMPONENT Moxifloxacin 1.0 ug/mL

Contributors (4)

8 Comments

  1. The link to the CT document is broken. I am not able to update the link, but it can be found here: https://jira.ihtsdotools.org/browse/IHTSDO-805?jql=text%20~%20%22artf7619%22

    Link to Ed Guide: 6.1.8 Substance

  2. Found this paper:

    https://academic.oup.com/cid/article/31/5/1209/329047

    It states "Methods that are typically used in the United States for susceptibility testing of MTBC are based on the ability of the isolate that is undergoing evaluation to grow on agar or in broth containing a single “critical” concentration of one drug. The critical concentration of a drug represents the lowest concentration that inhibits “wild” strains"

    Further it states that "The primary drugs that are recommended by the NCCLS subcommittee for testing against isolates of MTBC are isoniazid (at 2 concentrations) and rifampin, ethambutol, and pyrazinamide (1 concentration of each)."

    ...and then lists other antibiotics (with strengths) for other mycobacteria.


  3. Daniel,

    Following our meeting, if this can help, I can send you a package insert corresponding to those 'gradient strip' tests.

    • a generic one explaining how those test work, including Amp/sulb 
    • a different case is also of interests, the so called ARD strips in LOINC 

    Also available is the LOINC code list for those products. 

    just let me know

    Xavier

    1. Xavier, thanks, that would be helpful. /Daniel

  4. Daniel,

    I am not allowed by the system to insert files. Can you give me you mail address so that I'll send those directly to you.

    Xavier

    1. I've added an attachment box top right, or my email is daniel.karlsson@socialstyrelsen.se

  5. Outline of approaches for (1) and (2) make sense, but agree case (3) is problematic.

    I can see the temptation to extend the model so that components can be mapped not only to a substance or VTM, but also to an AMP combining a VTM with a basis of strength. But I don't really like it; the concentration quoted is the final concentration of the substance within the culture medium (and therefore the minimum tissue concentration that must be reached in the patient to be effective). Its unrelated to the particular basis of strength of the particular antibiotic product used to achieve that agar or tissue concentration. It might get the right 'words and numbers' into the Frame, but its very different semantics. Trouble is, adding the 'correct' semantics for this edge-case won't be pretty.

    1. The drug product concepts would not be therapeutic drugs but diagnostic products. The re-usability of the therapeutic drug attributes for these should be considered carefully, but the case that the strength of the substance within the diagnostic product in this specific diagnostic method is a proxy for tissue concentration does not have to be an issue. Then again, the number of diagnostic products for this purpose is limited and thus making them all primitive would have limited negative impact.