My experience* with electronics in general is that with 1 cell, a low-voltage problem shows up with a dim LCD screen. My multi-cell devices pretty much all work normally with Eneloops in place of alkaleaks. My Texas Instruments complicated calculator works perfectly on NiMHs. A "Low Battery" indicator on that device means "Charge the batteries this month" (I use it infrequently). Eneloops do a great job holding a fairly high voltage, only a few tenths lower than an open-circuit fresh alkaleak.
The best option would be to contact the manufacturer and get an answer from them. If you are feeling adventurous* you might get a fairly-drained set of Eneloop AAAs and take a series of readings, alternating with alkaleaks. If you get comparable values, you might accept it as "Good enough." I have family who take blood pressure medication based on these readings. If your safety depends on good readings, please use the meter as suggested by the manufacturer.
*Please be careful with devices that you make medical decisions with!
