What tests should be done after a tick bite? - briefly
Serologic testing for Lyme disease (ELISA followed by Western blot) is recommended if the tick was attached for more than 36 hours or originated from a region where the infection is common; additional PCR or serology for Anaplasma, Babesia, and Ehrlichia should be considered based on geographic exposure and clinical presentation.
What tests should be done after a tick bite? - in detail
After a tick attachment, evaluate the risk of pathogen transmission based on tick species, geographic area, and attachment duration. Immediate assessment includes a thorough physical examination for erythema migrans, regional lymphadenopathy, fever, or neurologic signs. Laboratory investigations should be tailored to the most common tick‑borne agents in the region.
- Serologic testing for Borrelia burgdorferi – enzyme‑linked immunosorbent assay (ELISA) followed by immunoblot confirmation. Initial sample collected at presentation, repeat after 2–4 weeks if early disease is suspected.
- Polymerase chain reaction (PCR) for Borrelia DNA from skin biopsy of a rash or from blood when disseminated infection is suspected.
- Complete blood count with differential – leukopenia or thrombocytopenia may indicate Anaplasma, Ehrlichia, or Babesia infection.
- Liver function panel – elevated transaminases support diagnosis of Anaplasmosis, Ehrlichiosis, or Babesiosis.
- Serology for Anaplasma phagocytophilum – indirect immunofluorescence assay (IFA) or ELISA, with convalescent sample for seroconversion.
- Serology for Ehrlichia chaffeensis – IFA or ELISA, repeat testing for rising titers.
- Babesia microti detection – thick‑blood‑smear microscopy, PCR, or serology; consider repeat testing if initial result is negative and symptoms persist.
- Rickettsia rickettsii testing – indirect immunofluorescence assay; early disease may require empiric therapy before results.
- Tick‑borne encephalitis virus – IgM and IgG enzyme‑linked immunosorbent assay; cerebrospinal fluid analysis if neurologic involvement is present.
- Additional pathogen panels (e.g., Powassan virus, Heartland virus) when epidemiologic data suggest exposure.
If the tick is identified as Ixodes scapularis or Ixodes ricinus and has been attached for ≥ 36 hours in an endemic area, a single dose of doxycycline (200 mg) may be administered as prophylaxis against Lyme disease, provided no contraindications exist.
Follow‑up testing should be scheduled at 2‑week intervals for serologic conversion and at 4‑week intervals for PCR if initial studies are negative but clinical suspicion remains. Continuous monitoring of symptoms guides the need for repeat or expanded testing.