Measurement of porphobilinogen in urine by a simple resin method with use of a surrogate standard.
In this method for urinary porphobilinogen (PBG), urine is added to Bio-Rad AG1-X2 (200-400 mesh) acetate resin under alkaline conditions and mixed. After two water washes, the adsorbed PBG is eluted with acid and reacted with Ehrlich's reagent (p-dimethylaminobenzaldehyde). Quantification is by comparison of the color developed with that of a PBG standard similarly treated or of a calibrated methyl red solution. The precision of assay of PBG at 20 and 50 mumol/L is 1.4% and 0.9% within-batch and 4% and 3.9% between-batch, respectively. The analytical recovery is about 90%, a proportion that appears to be inherent in the resin method. The proposed method (y) agreed well with the method of Mauzerall and Granick (x; J Biol Chem 1956;19:435-46), yielding the regression equation y = 0.957x + 2.9 (r = 0.993, n = 26). Good agreement was achieved with results determined from the PBG and the methyl red standards. The proposed method is inexpensive, simple to perform, and suitable for routine and emergency use.
Buttery
J E
JE
Department of Clinical Chemistry, Queen Elizabeth Hospital, Woodville, South Australia.
Stuart
S
S
D000085:Acetates; D001547:Benzaldehydes; D006801:Humans; D011162:Porphobilinogen / Q000652:urine*; D011786:Quality Control; D012044:Regression Analysis; D012116:Resins, Plant
D000085:Acetates; D001547:Benzaldehydes; D012116:Resins, Plant; D011162:Porphobilinogen; C510241:p-dimethylaminobenzaldehyde