The amount of a all-trans-retinol dehydrogenase [NAD(+)] ADH1B when measured in blood serum. The trait is OBA_2040514 (level of all-trans-retinol dehydrogenase [NAD(+)] ADH1B in blood serum). Also known as: blood serum all-trans-retinol dehydrogenase [NAD(+)] ADH1B amount.