title: Quality control of acid phosphatase assay improved by direct reconstitution of lyophilized control materials with citric acid.
abstract: Current quality control of assays of acid phosphatase (EC 3.1.3.2) with thymolphthalein substrate is inadequate when certain control-suppliers' instructions are followed for reconstituting and stabilizing human lyophilized control material. If such materials are reconstituted with a citric acid solution, then stored frozen, control vial-to-vial variability is minimized, as are losses of activity in freshly reconstituted controls and losses during room-temperature storage of the control material. Effects of pH of the reconstituting solution on the acid phosphatase activity of human lyophilized controls are also discussed.
mesh_terms: D000135:Acid Phosphatase / Q000592:standards*; D001322:Autoanalysis; D002951:Citrates; D019343:Citric Acid; D005612:Freeze Drying; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011786:Quality Control; D013223:Statistics as Topic
chemical_list: D002951:Citrates; D019343:Citric Acid; D000135:Acid Phosphatase