Adjective
methylmalonic (not comparable)
Relating to methylmalonic acid or its derivatives
I personally have found that urine methylmalonic acid is superior to serum, possibly because it’s more concentrated in urine than in the blood. Source: Internet
Urine methylmalonic acid is thought to be more sensitive than serum methylmalonic acid as a marker, because MMA is more concentrated in the urine than it is in the serum. Source: Internet