Example 7 - Direct and indirect detection of measles virus


This example illustrates serological measles diagnostics using IgM and IgG determination, as well as an avidity test and a measles PCR.


The procedures illustrated in this example are:
  • Immunoassay for antibody detection - Enzyme immunoassay for avidity test
  • PCR

Immunoassays that test for the presence of antibodies are used to determine measles IgG or IgM antibodies.

  • In accordance with the rules for handling semantics, LOINC codes are used that specifically describe the analyte as "Measles virus IgM Ab" or "Measles virus IgG Ab". The "property" [ACnc] allows for quantitative information as a response.
  • The LOINC codes "21503-8 Measles virus IgM Ab [Presence] in Serum" and "20479-2 Measles virus IgG Ab [Presence] in Serum" are LOINC codes that, in accordance with the rules for handling semantics, do not contain methods but are specific to the specimen (the "system" axis). Since serum, plasma, and cerebrospinal fluid are frequently used as specimen for antibody determinations, the aim is to apply for LOINC codes that, in accordance with the rules for handling semantics formulated for ARS, are non-specific for the specimen (the "system" axis) and the method (the "method" axis).
  • The response to the LOINC code is a quantitative value. To assess the quantitative value, which can vary depending on the test kit used, the reference range of the test result is specified here as "Observation.referenceRange".

The LOINC code "104428-8 Measles virus IgG Ab avidity [Ratio] in Serum by Immunoassay" is available for avidity testing.

  • Since the avidity test can also be performed using different specimen such as serum, EDTA plasma, heparin plasma, and citrate plasma, the aim is to apply for a specimen- and method-nonspecific LOINC code for avidity as well.

The LOINC code "48508-6 Measles virus RNA [Presence] in Specimen by NAA with probe detection" is available for the detection of measles RNA.



 

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