Diagnosis of mycotic infections is despite the immense effort devoted to this problem still very inaccurate. A new and promising method is the polymerase chain reaction, PCR, which theoretically can detect a single cell. In their original study the authors decided to develop a new method for the detection of fungi by PCR and to compare this examination with post-mortem findings. Thus it was possible to determine sufficiently reliably the sensitivity and specificity of the method. For the detection of fungi the authors selected the sequence coding for a small subunit of ribosomal RNA (18S rDNA). The method is able to detect the amount of DNA from some 10-100 cells. The sensitivity was 90% and the specificity 92%. The method is so far too laborious for common practice, its simplification would be however very useful.