National Registry in Clinical Chemistry

CLINICAL CHEMISTRY, Vol. 24, No. 4, 1978 731 variation of 5.7% was obtained at a level of 11 nmol/ml per hour. The figure shows the levels of erythrocyte uroporphyrinogen I synthase detected in three generations of a family with AlP. The level of activity of the proband (W.1) was just within the statistical reference range. Her father (ffl.I) and daughter (V.3) had values for actiVity that were 43% of the mean value of the reference range. These activities are similar to those in affected subjects in the Scandinavian family described in Peterson et al. It is clearly important to detect the latent as well as the overt forms of this potentially disabling disease, precipitatable by drug therapy, as early as possible in life. I would therefore like to recommend the use of the Peterson method for the detection of AlP, but at the lower substrate concentration of 20 nmol/liter. This lowering of the cost per test should influence its acceptability in many countries.