Human fingernails are an important material used to identify individuals in forensic medicine as well as a source of DNA for genetic analyses in different fields of study. Nail clippings have many advantages, such as stability and suitability for long-term storage, easy non-invasive sampling and simple transport. On the other hand, the structure of a fingernail (presence of keratinized cells) requires a more complicated DNA extraction method than DNA extraction from blood cells. Therefore, it is advantageous to use a direct PCR method that does not require a DNA isolation step. This method was used on fingernails for the first time by Tie et al., and by Ottens et al. The benefits of the method are simplicity, reducing the possibility of contamination and time- and cost-saving. We used this innovative method for donor-derived DNA analysis on the fingernails of 30 acute myeloid patients (AML) with long-lasting complete donor chimerism in their peripheral blood after the first allogeneic hematopoietic stem cell transplantation (allo-HSCT).