The potential of reducing AST testing in hospital settings

Area of Science:

• Clinical Chemistry
• Diagnostic Testing
• Biomarker Analysis

Background:

• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are commonly ordered together to assess liver health.
• ALT is more specific for liver injury, and AST and ALT levels often correlate, suggesting potential redundancy in AST testing.

Purpose of the Study:

• To evaluate the clinical utility and potential reduction in AST testing when ALT results fall within established reference intervals (RI).

Main Methods:

• Analysis of paired AST and ALT results from adult patients (January 1, 2017 - December 31, 2017).
• Calculation of the frequency of AST and ALT results within and above RI.
• Investigation of sample origins by clinical location.

Main Results:

• Out of 87,704 paired samples, eliminating AST tests when ALT was within RI could reduce testing by 73.2% in males and 66.9% in females.
• This approach would miss 7.4% of elevated AST in males and 3.8% in females.
• In outpatient clinics, 79% of males and 73% of females had normal ALT with elevated AST in only 4% and 3%, respectively.

Conclusions:

• The low incidence of elevated AST with normal ALT supports restricting AST testing to cases with elevated ALT.
• A phased implementation, starting with outpatient clinics, is recommended for AST testing reduction.