Chloridometers are used to determine the concentration of chloride ions in biological fluids. For example, fish plasma chloride ion concentration is measured to gauge the effects of stress on osmoregulation in aquacultures. A small quantity of plasma (10 μL) combined with an acid reagent results in a chemical reaction that ultimately provides a concentration measure of chloride ions in meq/L.
Because they require alternating current, chloridometers are not portable and are better suited to a "bench-top location". This may necessitate freezing  biological fluid specimens collected in the field for later analysis.
Chloridometers represent the most common use of coulometry in clinical biochemistry.