What blood tests should be done if a tick bites? - briefly
Recommended investigations include serologic screening for Borrelia burgdorferi with «ELISA» and confirmatory «Western blot», PCR or serology for Babesia microti, Ehrlichia species, Anaplasma phagocytophilum, and, where endemic, testing for tick‑borne encephalitis virus or Rickettsia rickettsii. Samples are usually drawn 2–4 weeks after exposure to permit antibody development.
What blood tests should be done if a tick bites? - in detail
A tick bite can transmit pathogens that require specific laboratory evaluation. Initial assessment should include a complete blood count (CBC) to detect leukocytosis, anemia, or thrombocytopenia, which may indicate early infection or systemic response. Liver function tests (ALT, AST, bilirubin) help identify hepatic involvement commonly seen with certain rickettsial diseases.
Serologic testing is essential for confirming exposure to tick‑borne agents. Recommended assays include:
- Immunofluorescence assay (IFA) for antibodies against Borrelia burgdorferi (Lyme disease) and Anaplasma phagocytophilum (anaplasmosis). Paired acute and convalescent samples improve diagnostic accuracy.
- Enzyme‑linked immunosorbent assay (ELISA) for Babesia microti antibodies, followed by confirmation with indirect fluorescent antibody (IFA) or PCR when indicated.
- IFA or PCR for Rickettsia species, especially Rickettsia rickettsii (Rocky Mountain spotted fever) in endemic regions.
Molecular diagnostics complement serology. Polymerase chain reaction (PCR) testing on whole blood or plasma should be performed for:
- Borrelia DNA detection in suspected early Lyme disease before seroconversion.
- Anaplasma and Ehrlichia DNA in cases of acute febrile illness with leukopenia or thrombocytopenia.
- Babesia DNA to confirm babesiosis, particularly in immunocompromised patients.
Additional tests may be warranted based on clinical presentation:
- C‑reactive protein (CRP) and erythrocyte sedimentation rate (ESR) to assess inflammatory activity.
- Renal panel (creatinine, BUN) for potential kidney involvement in severe infections.
- Coagulation profile (PT/INR, aPTT) if disseminated intravascular coagulation is suspected.
Timely ordering of these investigations, guided by epidemiology, symptomatology, and exposure history, facilitates accurate diagnosis and appropriate treatment of tick‑borne diseases.