Macro-AST as a cause of isolated chronically elevated AST activity – two case reports

Czech version

Authors: I. Hejlová ¹; J. Komrsková ²; E. Sticová ³; P. Trunečka ⁴; J. Špičák ¹; J. Franeková ²
Authors‘ workplace: Klinika hepatogastroenterologie, Transplantcentrum, IKEM, Praha ¹; Oddělení klinické biochemie, Pracoviště laboratorních metod, Komplement, IKEM, Praha ²; Pracoviště klinické a experimentální patologie, Transplantcentrum, IKEM, Praha ³; Transplantcentrum, IKEM, Praha ⁴
Published in: Gastroent Hepatol 2016; 70(2): 138-140
Category: Hepatology: Case Report
doi: https://doi.org/10.14735/amgh2016138

Overview

Introduction:
Some enzymes, e.g., aspartate aminotransferase (AST), can form high molecular mass complexes, referred to as macro enzymes, which persist in the serum and cause increased serum activity.

Case study:
We describe two cases of isolated chronically elevated AST activity in two young asymptomatic females (20- and 21-years-old). Both patients denied alcohol consumption, use of medication, or increased muscle activity. ALT activity and other initial laboratory studies were normal. Detailed investigation did not reveal any disease of liver, muscles, heart, or thyroid gland, or the presence of celiac disease. This led us to consider the possibility of macro-AST. A polyethylene glycol precipitation assay was performed, which revealed 92% and 79% polyethylene glycol precipitable activity, confirming the presence of macro-AST in both patients.

Conclusion:
Isolated chronically elevated AST activity may be caused by the presence of macro-AST. Confirmation of macro-AST positivity may help avoid expensive and invasive investigations.

Key words:
aspartate aminotransferase – AST – macro-AST – macroenzymes

The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.

The Editorial Board declares that the manuscript met the ICMJE „uniform requirements“ for biomedical papers.

Submitted:
3. 12. 2015

Accepted:
26. 1. 2016

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