title: [Macroenzymes: an interesting laboratory finding, without clinical relevance].
abstract: Macroenzymes are complexes of serum enzymes with proteins which have a higher molecular weight and longer plasma half-life than the normal enzyme. The presence of macroenzymes is suggested by finding increased serum enzyme activity, not associated with symptoms. Thus, macroenzymes can cause diagnostic errors and the performance of unnecessary tests or invasive procedures. We describe 2 patients with highly elevated serum levels of lactate dehydrogenase (LDH) and creatine kinase (CK) due to formation of complexes with immunoglobulin G. 1 patient had LDH of 4500 u/L but was otherwise normal and in the second CK was elevated with no evidence of ischemic heart disease. Awareness of the phenomenon of macroenzymes may save the patient long and sometimes invasive investigation.
authors.affiliation: Hematology Dept., Tel Aviv-Sourasky Medical Center.
authors.forename: C
authors.initials: C
authors.lastname: Perry
authors.forename: H
authors.initials: H
authors.lastname: Peretz
authors.forename: E
authors.initials: E
authors.lastname: Graf
authors.forename: O
authors.initials: O
authors.lastname: Ben-Tal
authors.forename: A
authors.initials: A
authors.lastname: Eldor
mesh_terms: D000328:Adult; D001219:Aspartate Aminotransferases / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism*; D004796:Clinical Enzyme Tests; D003402:Creatine Kinase / Q000097:blood*; D003951:Diagnostic Errors; D005260:Female; D006207:Half-Life; D006331:Heart Diseases / Q000175:diagnosis; D006339:Heart Rate; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000096:biosynthesis; D008875:Middle Aged; D011485:Protein Binding; D015203:Reproducibility of Results
chemical_list: D001798:Blood Proteins; D007074:Immunoglobulin G; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases; D003402:Creatine Kinase