Tjaša Žagar
Klinični oddelek za gastroenterologijo, hepatologijo in nutricionistiko, Pediatrična klinika, Univerzitetni klinični center Ljubljana, Ljubljana, Slovenija

Rok Orel
Klinični oddelek za gastroenterologijo, hepatologijo in nutricionistiko Pediatrična klinika, Univerzitetni klinični center Ljubljana, Ljubljana, Slovenija in Katedra za pediatrijo, Medicinska fakulteta Ljubljana, Ljubljana, Slovenija

Abstract

We present a case of cryptogenic elevation of aspartate aminotransferase (AST) activity. AST is an enzyme found in many tissues, so the serum activity of this enzyme may be elevated in various diseases. If there is an isolated increase in AST, we are therefore faced with a diagnostic challenge and many diseases must be ruled out. When most diseases have been ruled out with a high probability, it is referred to as a cryptogenic increase in AST activity. Some studies have shown that part of this increase can be explained by macroenzymes, more specifically by macro - AST. In the case presented, we also suspected that the increased AST activity was due to macro - AST. As the determination of macro - AST is not possible in the laboratory of the University Clinical Centre Ljubljana, it has not been possible to confirm or refute the diagnosis.

Key words: aspartate aminotransferase (AST), macroenzymes, purpura, thrombocytopaenia