Heparin interferes with albumin determination by dye-binding methods.

Heparin, when added in vitro at rather high concentrations (400--1000 kilounits/L) as an anticoagulant, interferes with albumin determination by bromcresol green by forming an insoluble precipitate with this dye. The interference is much less with bromcresol purple. It can be abolished by addition of hexadimethrine bromide.