Difficulty with interpretation of AChE levels arises for several reasons including a variation in cholinesterase inhibition from different types of OP agents [9], the wide normal range for both kinds of AChE (plasma cholinesterase and red cell cholinesterase), irreversible inhibition (“ageing”) by a proportion of the enzyme, and the fact that inhibition can be non specific due to other factors that can reduce AChE levels such as concurrent chloroquine therapy, or conditions like pernicious anaemia [1,3]. Here, BCHE is linked to pernicious anemia.