The personna Med Prep are the exact same blade as the Personna Lab Blue. The only difference is that the Med Prep blades have been washed to remove oils and sterilized.
Technically the "Personna Lab Blue's" are old stock, some time ago they transitioned to the Accutec/Accuforge brand/name. If you look around you can find NOS Lab Blues for sale at fairly reasonable prices and the current production Accuforge blades (I think they are in a black wrapper) aren't terribly expensive either.
I have the original personna lab blue blades and really like them, I think they are among my top performers...definately more comfortable and longer lasting than feather blades.