Some observations on the assay of arylsuphatase A in urine

A method for the measurement of arylsulphatase A (ASA) in urine is assessed. Urine samples should be stored refrigerated at 4 degrees C and not deep frozen prior to dialysis. The within-batch coefficient of variation of method, in the normal range, is 6.7%. The major source of imprecision is the dialysis step. The normal range is assessed and results are expressed as units per mole creatinine.