Hiv blot: line or immunoblot

General
1

The LOINC guide differentiates Immunoblot from Lineblot.

Many HIV blots are not performed by electrophoresis. It is often peformed by “membrane strips that are pre-coated with a specific set of antigens” so I would think it is a lineblot. However in the LOINC database for HIV I can only find immunoblot. Is this an ommission or did I somehow not correctly interpret the difference between immunoblot and lineblot as defined by LOINC? See below for the description in the guide. (the last sentence is not entirely clear to me, but I would think when using a precoated membrane strip in the lab with a serum with mixed antibodies it still classifies as a lineblot).

"2.7.3 Immunoblot and Line blot Methods

LOINC has two different Methods for Immunoblot (IB) and Line blot. IB is used in cellular and molecular biology to identify a specific protein in a complex mixture extracted from cells. Gel electrophoresis separates polypeptide chains (subunits) into bands according to their molecular weight. The bands are transferred onto a membrane and incubated with a primary and secondary antibody to visualize the target subunits. The Line blot Method is similar in that it utilizes membrane strips that are pre-coated with a specific set of antigens in parallel lines that are incubated with antibodies in order to detect the targets of interest. However, LOINC distinguishes the two Methods based on when the electrophoretic/chromatographic separation occurs. In IB, the separation occurs in the testing laboratory, whereas in Line blot, it occurs during the manufacturing step and not in the testing laboratory."

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Hi Bram!

Recently, I had the same doubt. I’m going to go further. Some confirmatory tests (such as the BioRad Geenius) are categorized in their own package inserts as immunochromatographic assays (with no mention of Western blot, immunoblot, or line blot). In these cases, the method could be classified as Rapid Immunoassay.

There is at least one code following this philosophy: 80203-3, which was specifically created for the Geenius BioRad HIV1/2 Supplemental Assay. However, there is a lack of related terms that could be useful.

Code 80203-3 expects the results to be identifiers (HIV1, HIV2, HIV1 & HIV-2), but there are no codes to express these results in an atomic way (HIV1: Positive/Negative/Indeterminate, and the same for HIV2). Additionally, there are no codes for specific proteins with this method (or with the line blot method).

For example, for the HIV-1 p24 Ab, you have:

I believe that, for consistency, there should be codes for the Ab-anti-HIV proteins using the same method as the code used to report the result

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Thanks for your additions! I am pretty sure lineblot should be activated as well, but before asking Regenstrief I will also discuss what other elements we would need. However there are already so many codes for HIV, perhaps aiming for methodless components and post-coordinate technique would be preferable? Kind regards!