ADNI merge ABETA vs UPENN ABETA

[Pav Kalinowski]

Hello helpful people.

I'm trying to calculate ab42/ab40 as well as TTAU/AB42 for participants.

I've read in the adnimerge documentation that the csf adni and tau for the merge was taken from UPENNBIOMK_MASTER.csv, however when i merge these datasets to check I'm getting different scores for both TAU and ABETA. 

Does this mean that ABETA in one of these documents is actually AB40?

If not, why would there be different scores if the UPENNBIOMK_MASTER was used in ADNImerge?

[Danielle J Harvey]

Hi Pav,

 

I believe ADNIMERGE uses the values from the Roche Elecsys platform (some of the more recent UPENNBIOMK files that are available on the website). UPENNBIOMK_MASTER contains the measurements from the previous assay that was used.

 

Danielle

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[Pav Kalinowski]

Thanks for this Danielle,  so i've downloaded  UPENNBIOMK9_04_19_17.csv and that matches the adnimerge data. This leads me to believe that the ABETA is actually ABETA 42 in both  UPENNBIOMK_MASTER and  UPENNBIOMK9_04_19_17 and that only UPENNBIOMK12_01_04_21.csv (the most recent) has ABETA 40. So creating the ratio will not be possible.

I'm curious though as to which dataset to use . I can't find any clarification in any of the methods pdfs. I'm also not sure what the master is to be used for if the ADNImerge uses  UPENNBIOMK9_04_19_17 .

[Danielle J Harvey]

Hi Pav,

 

The ADNI Biomarker Core switched to using the Roche Elecsys assay since they felt that was better than the original assay they had been using.  UPENNBIOMK_MASTER contains Abeta42, since originally, only Abeta42, tau and p-tau were measured. As you say, UPENNBIOMK9_04_19_17 also only contains Abeta42. It looks like UPENNBIOMK10_07_29_19 contains both Abeta40 and Abeta42 (UPENN CSF Biomarkers Elecsys [ADNI3, batch I]) as does UPENNBIOMK12_01_04_21.

 

I believe the general guidance from the Biomarker Core is to use the values within a file for a participant (RID), but that you can combine participants from different files (as long as it was the same assay) to increase your sample size….you just don’t want to use some visits for person A from one file and other visits for person A from another file.

 

The MASTER file was created as a way for ADNI data users to understand the large number of files that had been submitted with CSF markers since the start of ADNI…that was made available before the Biomarker Core started to use the Roche Elecsys system and to be consistent with our data sharing policy, those data are still available.

To view this discussion on the web visit https://groups.google.com/d/msgid/adni-data/34e8fb34-3ab8-4cd7-98a4-04a25684f6ean%40googlegroups.com.

[Pav Kalinowski]

Thank you Danielle