Review of phosphate methodologies.

A description of the extensive literature on the methodologies for the determination of serum phosphate has been reviewed. The evolution of the various phases of the analytical techniques developed in the last century leading to the simplified, sensitive and accurate procedures of the present have been presented in some detail. A procedure involving a simple direct reaction for the determination of inorganic phosphate in serum using ascorbic acid as a reducing agent and a citrate-arsenite mixture as a stabilizing-sensitizing reagent, all in a semi-aqueous medium containing dimethysulfoxide and the detergent Teepol 610 is recommended. Jaundice and mild hemolysis are noninterferencts and turbidity from severe lipemia is easily overcome by reversing the sequence in which reagents are added because citrate binds molybdate in preference to phosphate. Thus, the serum blank and the reacted serum are identical in makeup thereby yielding an idealized correction for irrelevant absorption. Reaction characteristics and potential errors are included in the discussion of the procedure.