# Set reference line for transaminase tests

Use this option to specify a custom reference line for the alanine transaminase test (ALT) and aspartate transaminase test (AST) to be drawn on the Hy’s Law plot.

Note: This same custom threshold is used for both ALT and AST.

### To Set a Reference Line for the Transaminase Tests:

| 8 | Check the Set custom reference lines for Hy’s Law plots box to enable this option.

| 8 | Either enter the desired value in the text field or move the slider to the right or to the left to change the value.

Tip: To change the scale of the slider, right-click on the slider and select
from the pop-up menu. Change the upper or lower boundaries in the that appears, to rescale the slider and click
.