Following this because I am in the same place and have no idea what to ask at the appointment.

Reference ranges differ between labs, so comparing two reports is close to meaningless.

You have two changes at once here. You cannot attribute anything until one of them moves.

Reference ranges differ between labs, so comparing two reports is close to meaningless.

A plausible mechanism is not an outcome, and this class is the textbook example. How long have you been on probiotics?

Read methods.

Reference ranges differ between labs, so comparing two reports is close to meaningless. Not on a backup routine but the pattern is familiar.