prn MSLT's

A doctor asked on the AASM message board about prn (as needed) MSLT's. In his sleep medicine group, doctors sometimes order a nocturnal polysomnogram to evaluate for OSA, with instructions to the technicians to perform an MSLT if OSA is not found.

Should the practice of "prn" MSLT be abandoned? Is it a bad idea?

Here is my answer to the the doctor's question?

yes and yes.

If you think someone has narcolepsy/idiopathic hypersomnia it is reasonable to order a psg/MSLT with instructions that the MSLT be canceled if OSA is present (with the sleep physician being avaliable in the am to review the psg in borderline cases).
I think it is unreasonable and puts too much responsibility on the techs to have them decide whether an MSLT is neeed on large numbers of patients being evaluated for OSA.