Biomarker data

[alan hopkins]

Hello,

When examining the biomarker data in ADNI, I have noticed that both NfL and GFAP have two potential readings, one suffixed with "_F" and the other with "_Q". The "_F" value appears to represent the measured concentration obtained directly from the assay, whereas the "_Q" value appears to represent a quality-controlled or ratified value rather than the direct measurement.

My assumption is that when both an "_F" and a "_Q" value are available for an NfL or GFAP measurement, the "_Q" value should generally be preferred.  Is this correct?  Has this guidance been formally documented anywhere?  In addition, are the "_F" and "_Q" values directly comparable, and if no "_Q" value is available, is it appropriate to use the corresponding "_F" value instead?

Clarification on this matter would be greatly appreciated.

Kind regards 

Alan

[Danielle J Harvey]

Hi Alan,

 

The data dictionary specifies that _Q means that the measure comes from Quanterix, while _F means that the measure comes from Fujirebio. These are two different platforms. You can also refer to the corresponding methods document to the dataset (available in the same section where you found the data) for more details about the two platforms.

 

Danielle

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