The direct detection of the Borrelia burgdorferi sensu lato clearly demonstrates the existence of Lyme borreliosis. The practical implementation of this method is lengthy and has a low diagnostic yield. This is because the pathogen is difficult to culture and the small number of bacteria in the samples (tissue or body fluids) is hard to detect by microscope. In such cases not even the newly introduced genetic tests have a sufficient sensitivity.

The DualDur cell technology medium (DD medium) was developed by Dr. Béla Pál Bózsik through the practical application of research data in the laboratory diagnosis of Lyme disease. It can be used to prepare the blood sample for the dark-field microscopic test of the pathogenic bacterium. DD medium prevents the formation of artefacts and protects the extremely vulnerable Spirochetes, while preserving their characteristic motility, which helps in their detection.

Several decades of experience of our research work confirm that Borreliae can be readily identified using dark-filed microscopy if the samples containing Borrelia are treated with the DD medium and are concentrated, even if the number of bacteria in the original sample is low. Additionally, other spirochetes can also  be identified.