Reported Awareness and Use of Pyridoxal-5'-Phosphate Supplementation in Alanine Aminotransferase and Aspartate Aminotransferase Assay Reagents: A Survey by the College of American Pathologists Clinical Chemistry Committee.

Context.—: Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) assay reagents are available both with and without supplementation with pyridoxal-5'-phosphate (P5P; the active form of vitamin B6), a catalytic cofactor required for their enzymatic reactions. Nonsupplemented assays may miss ALT or AST elevations in patients with vitamin B6 deficiency.

Objective.—: To assess awareness and adoption of ALT and AST reagents that are supplemented with P5P.

Design.—: A 4-question survey about ALT and AST reagent supplementation with P5P was included in the College of American Pathologists General Chemistry and Therapeutic Drugs (C program) proficiency testing 2023 B mailing.

Results.—: Overall, 38% (1651 of 4304) of responding laboratories reported using ALT and/or AST reagent supplemented with P5P. P5P supplementation was more common for nonacademic hospital/medical center laboratories (44%; 713 of 1629) relative to other settings. Of the laboratories that reported not using P5P-supplemented reagents, few (5%; 141 of 2611) cited plans to convert in the future. Despite the availability of P5P-supplemented reagents from several major assay manufacturers, the most common stated barrier for adoption was that the laboratory's reagent manufacturer does not provide P5P-supplemented reagents.

Conclusions.—: There is a lack of awareness of the existence and benefits of P5P-supplemented ALT and AST reagents. There is a need for ALT and AST assay manufacturers to clarify and standardize the P5P status of ALT and AST reagents.