There is currently only one commercially available test that directly detects living Borrelia spirochetes in blood — DualDur. Unlike antibody tests (ELISA, Western blot), PCR and antigen tests, DualDur provides visual image evidence of the bacterium itself.
Standard tests (ELISA + Western blot) measure the immune response — not the bacterium. Antibodies can be absent early on, in immunosuppression, or when the spirochete hides intracellularly and in biofilm. They can also persist for years after the infection has resolved.
PCR and antigen tests are also indirect: they detect DNA fragments and protein markers respectively, which can remain without the bacterium being alive. Because it is living spirochetes that cause and sustain Lyme infection, a direct test is required to confirm an ongoing, active infection.
DualDur is a CE-IVD registered laboratory method in which a blood sample is treated with a cell-technology medium and then analysed using enhanced automated dark-field microscopy (AIM) combined with direct-stain immunofluorescence.
The result is concrete image evidence — the patient and treating doctor get to see the motile, living Borrelia spirochetes in the sample. The method was developed within an EU-funded Horizon 2020 project (Grant 805609) and validated in the EU's largest clinical Lyme diagnostics trial.
The DualDur protocol includes parallel screening for several common co-infections that are often transmitted by the same tick bite and can produce a symptom picture overlapping with Lyme disease.
Malaria-like parasite in red blood cells — fever, drenching sweats, haemolytic anaemia.
Intracellular bacterium — stretch-mark-like rashes, foot pain, neuropsychiatric symptoms.
Acute febrile illness, leukopenia, thrombocytopenia, raised liver enzymes.
Vasculitis, chronic inflammation, joint pain and neurological symptoms.
Because several co-infections can be present at once — and concurrent babesia + Borrelia is documented to be associated with more severe and longer illness (Krause et al., JAMA 1996) — combined screening is clinically valuable when investigating chronic complaints after tick exposure.
A selection of clinical trials, peer-reviewed publications, CE-IVD documentation and EU project reports describing the DualDur method and its diagnostic performance.
Prospective performance evaluation of the DualDur IVD system compared with PCR and serology.
Open sourcePeer-reviewed publication describing the optical method behind DualDur — direct visualisation of motile, living spirochetes.
Open sourceSummary: DualDur showed significantly higher sensitivity than ELISA, Western blot and PCR in the largest clinical Lyme diagnostics trial in the EU.
Open sourceCE-IVD registration, cell-technology medium, morphological identification of spirochetes, and why new direct methods are needed.
Open sourceThe EU-funded research project behind DualDur — automated dark-field microscopy for early and accurate Lyme diagnostics.
Open sourceThe manufacturer's own description of the method, scientific background and clinical results.
Open source