Detection of macro-creatine kinase and macroamylase by polyethylene glycol precipitation and ultrafiltration methods

Sara P. Wyness, Joshua J.H. Hunsaker, Sonia L. La'ulu, Lokinendi V. Rao, William L. Roberts

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Background: Macroenzymes may cause elevations in serum enzyme activity. Macroenzymes are not common; however their detection is important because they cause diagnostic confusion and therapeutic errors. Methods: We analyzed 2 of the most prevalent macroenzymes in the literature, macro-creatine kinase (macro-CK) and macroamylase, using 2 methods for detection, polyethylene glycol (PEG) precipitation and ultrafiltration (UF). Enzyme measurements were made using a Roche Modular Analytics P analyzer. Imprecision was assessed using quality control material. We evaluated 125 samples from apparently healthy subjects to establish reference intervals. For macro-CK comparison, 94 samples with activities > 200. U/l were analyzed with both PEG precipitation and UF and compared to electrophoresis. PEG precipitation and UF were compared for macroamylase detection using 130 samples with amylase activities > 110. U/l. Results: UF was more precise and demonstrated narrower reference intervals for both analytes. PEG precipitation and UF were able to detect true cases of macro-CK with overall agreement with electrophoresis of 79.8% and 80.9%, respectively. Both methods detected the same number of 'positive' macroamylase samples; however PEG precipitation resulted in a greater number of 'indeterminate' cases. Conclusion: This is the first report where UF has been shown useful for the detection of both macro-CK and macroamylase. © 2011.
Original languageEnglish (US)
Pages (from-to)2052-2057
Number of pages6
JournalClinica Chimica Acta
Volume412
Issue number23-24
DOIs
StatePublished - Nov 20 2011
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical

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