Turbidity as a cause of error in the L-alanine transferase (ALAT) method

When performing the ALAT-determination as recommended by the Scandinavian Committee on Enzymes, turbidity will develop due to a low ionic strength of the buffer. At the end of the pre-incubation period, the turbidity may still be developing, increasing the absorbance and lowering the ALAT-activity by 0-5 U/l. Turbidity and the error introduced in the assay, can be eliminated by increasing the ionic strength of the buffer by addition of NaCl.