What Do Specimen Numbers 1–10 Mean for CHEM-Class Laboratory Test Codes?

Dear LOINC Community Forum,

I came across the following laboratory test description:

“Glucose [Mass/volume] in Serum or Plasma --10th specimen”

It belongs to the CHEM class, and there are separate codes for specimens 1–9 as well.

If I am not mistaken, codes belonging to the CHAL or CHAL.ROUTINE properties and containing different specimen numbers are collected at certain intervals following the administration of a challenge (e.g., “Glucose [Mass/volume] in Serum or Plasma --5th specimen post lactose”)

However, I am now wondering what the specimen numbers signify for codes belonging to the CHEM class, where by definition, no challenge is administered.

Do they refer to blood collected in different tubes, a blood sample divided into multiple specimens, or a specific laboratory coding convention? Or does it indicate something else entirely?

I would greatly appreciate any clarification or insight into the meaning of these codes.

Thank you very much!

Ivona

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Hello Ivona and thank you for the question. You are correct in thinking about the clinically administered tolerance tests to a patient; they usually map to a specific dose of a challenge or will be noted with .

There are clinical trial labs however that may be administering to a cohort of participants with a protocol to follow. These would each be collected in separate tubes; they are not aliquots of one collection. There are several biomarkers in the LOINC database that allow for unspecified series of collections to be included [insulin, gastrin, prolactin, corticotropin, etc]

Hope this answers your question,

Pam

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In addition to Pam’s response, the numbers usually refer to separate specimens that are collected and not the blood sample divided into multiple specimens. LabCorp lists the following multiple specimen tests: Multiple-specimen Testing Guidelines | Labcorp

Cordially,

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