Screen vs Confirmatory Results

I am working at a client site. Their LIS drugs of abuse test codes are very specific for the drug/specimen (i.e. OXYM oxycodone for meconium, OXYC oxycodone for cord blood). The referral lab they send the specimens to report the drug test & method performed. Screening methods are reported with drug test (group i.e. AMPHETAMINES (test) negative (result) and 25 ng/ml (screen limit). Confirmatory drug test results same as the confirmatory - but also result the methodology used (i.e. LC/MS/MS).

So this presents a problem as to what LOINC to associate with our LIS test code…the screen or the confirmatory LOINC? Also, what do we do when there is not a LOINC for a drug/specimen combo…i.e. Barbiturates for Cord Blood. There currently is not a code provided…it is a “smart” thing to use the Unspecified Specimen LOINC? I keep reading about discouraging the use of the XXX system.

This client is NOT currently interfaced to this referral lab.


It appears the work is referred out. I would recommend asking the performing lab to provide the LOINCs they have mapped, if they’ve performed the mapping work already. The larger reference labs in the U.S. have completed this; some offer it on their websites. Depending on what specimens the reference lab offers the test on, they may submit for a new LOINC OR they may indeed use the XXX system (when the same assay is run on several specimens under one result code).

This is presuming your LIS has a result field open for each field coming back from the reference lab; you mentioned there’s not a direct systems interface in place, which would require that synchronization.

Please reply here if a portion needs to be discussed further.

Best Regards,


Hi Pam:

I did ontact the referral lab and was told that they do not yet provide LOINC info for their testing.

In that case, I’d ask if all inhouse testing is LOINC’d before taking on the send out referrals. No one else will be mapping the inhouse work, but the sendout lab is ideally responsible for mapping their own. (I know that isn’t always reality.) Maybe they’ll get started because your call triggered them. Also, sometimes the Customer Service rep doesn’t know what LOINC is, and you may be getting the wrong answer. The large labs such as LabCorp, Quest, Mayo, ARUP do offer LOINC. I understand NMS Labs has worked on theirs. MedTox was acquired last summer from LabCorp, so that should be in the corporate work queue.

If you decide to go forward with mapping the sendout testing, can you confirm the result fields build of the client’s LIS equals the report format of the performing lab? Do you have a catalog of all acceptable specimen types and method for each assay? Have you downloaded the most recent copy of the LOINC User’s Guide? Refer to the drug testing section for information on how the different methods used in the lab are treated in LOINC. If distinct specimens are used on discrete result fields, and there’s not current LOINCs, then submissions would need to be made. (Again, I’d really like to see the sendout lab do that, as the actual producer of the lab value). Leave those fields blank for LOINC in your site’s LIS; it shouldn’t be an issue.

Post again if you have any trouble,