 A combination of these biological features and technical feasibility of sampling, position cfDNA as a potential biomarker of enormous utility for example for autoimmune rheumatic diseases and tumors.It offers also a potential biomarker with its own advantages over invasive tissue biopsy as a quantitative measure for detection of transplant rejection as well as immunosuppression optimisation.However, this method lacks uniformity on the type of sample (plasma/serum/synovial fluid/urine), methods of sample collection/processing, free or cell-surface bound DNA, cfDNA extraction and cfDNA quantification, and also in the presentation and interpretation of quantitative cfDNA findings.