A sensitive method to quantify human cell-free circulating DNA in blood: Relevance to myocardial infarction screening

Objectives: Human cell-free circulating DNA (cf-DNA) derived mainly from cell apoptosis and necrosis can be measured by a variety of laboratory techniques, but almost all of these methods require sample preparation. We have developed a branched DNA (bDNA)-based Alu assay for quantifying cf-DNA in myocardial infarction (MI) patients. Design and methods: A total of 82 individuals were included in the study; 22 MI and 60 normal controls. cf-DNA was quantified using a bDNA-based Alu assay. Results: cf-DNA was higher in serum compared to plasma and there was a difference between genders. cf-DNA was significantly higher in MI patients compared to the controls. There was no correlation between cf-DNA and creatine kinase-MB (CK-MB), troponin I (cTnI) or myoglobin (MYO). In serial specimens, cf-DNA was sensitive and peaked earlier than cTnI. Conclusions: The bDNA-based Alu assay is a novel method for quantifying human cf-DNA. Increased cf-DNA in MI patients might complement cTnI, CK-MB and MYO in a multiple marker format. (C) 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.