MIMIC-IV: Flag and comments of NTproBNP in labevents

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Checked the online documentation: https://mimic.mit.edu/
  • Checked that your issue isn't already addressed: https://github.com/MIT-LCP/mimic-code/issues?utf8=%E2%9C%93&q=

Description

I am doing an analysis about NTproBNP (itemid=50963) and using the flag column (normal/abnormal) as my target. For this reason, I would like to know the specific cut-offs of the flag. Although the ref_range_lower and ref_range_upper are provided in the data, I still don't know where these cut-offs come from.

In the comments column it says: "Reference values vary with age, sex, and renal function. at 35% prevalence, NTproBNP values:. < 450 have 99% Neg pred value. >1000 have 78% Pos pred value. See online lab manual for more detailed information.".

However, I can not find the online lab manual in the online documentation. Does anyone know where can I find the information about the cut-offs?

Start with the MIMIC online documentation and the referenced labevents data for itemid 50963. Determine where the NTproBNP flag cutoffs and cited online lab manual are documented, then clarify or add that reference so the source of the cutoffs is discoverable.