Changes in AST and ALT Testing Going Into Effect Tuesday, February 25, 2025

Effective Tuesday, February 25, 2025, testing for ASPARTATE AMINOTRANSFERASE [LAB131] and ALANINE AMINOTRANSFERASE [LAB132] will be updated to standardize results across multiple laboratory sites within University of Iowa Health Care. This change will affect AST and ALT testing performed at Medical Center University, Iowa River Landing, and North Dodge laboratories. The clinical laboratory at the Medical Center North Liberty will also use these assays when that facility opens.

The new AST and ALT assays are supplemented with pyridoxal-5'-phosphate (P5P), also known as vitamin B6. P5P is a required co-factor for measuring AST and ALT activity. The use of assays with P5P supplementation enables accurate AST and ALT measurement regardless of a patient’s vitamin B6 status. This change is required as our instrument and assay vendor (Roche Diagnostics) is phasing out the current non-P5P-supplemented AST and ALT assays.

The following are impacts of this change:

• Results from the new assays will be approximately 20 – 30% higher than the current assays.
• Reference intervals for adults will change to the following:

	AST Ref. Interval	ALT Ref. Interval
Adult Male	0 – 50 U/L	0 – 50 U/L
Adult Female	0 – 35 U/L	0 – 35 U/L

• Reference intervals for children will also change. See the Laboratory Services Handbook for age- and sex-specific reference intervals: https://www.healthcare.uiowa.edu/path_handbook/index.html.
• Results from the new assays will trend on different Result Review lines in EPIC.

Sample type (Light Green PST Vacutainer) and turnaround time (within 1 hour of specimen receipt) will remain unchanged.

Questions should be directed to Anna Merrill, PhD (678-8400, anna-merrill@uiowa.edu) or Matthew Krasowski, MD, PhD (384-9380, matthew-krasowski@uiowa.edu).