Regarding Multiple Measurements in CSF and Plasma Datasets

[jahnavi adusumilli]

Hello everyone, 

An issue I encountered in a few of the CSF and plasma datasets is multiple measurements. For a few cases, there appear to be multiple measurements recorded for the same patient (same RID), under the same VISCODE2 and EXAMDATE. In other words, a single patient visit has two different values for the same variable.

Could you please advise on how best to handle these duplicates when organizing the data along a timeline? Specifically, I am unsure whether I should:

• Keep the earliest measurement,
• Keep the latest measurement, or
• Retain all available measurements for that visit.

I would appreciate your guidance on the most appropriate approach for this analysis.

Thank you.

[Danielle J Harvey]

Often samples are rerun in later batches to help with differences in kits used to process the samples. The Biomarker Core has generally recommended using the earlier processed sample (earlier batch). I recommend reviewing the methods documents associated with the specific datasets you are working with (if you haven’t already) to see if they provide any recommendations for deciding which one to use. Those documents also typically include a contact for questions, as the folks who generated the data are generally in the best position to provide guidance.

 

Danielle

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[jahnavi adusumilli]

Thank you, Danielle.

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