How to perform tests after a tick bite? - briefly
After a tick bite, obtain a blood sample for Lyme disease screening (ELISA) and confirm any positive result with a Western blot; also request serologic or PCR tests for other region‑specific tick‑borne pathogens as indicated. Promptly consult a healthcare provider to interpret the findings and determine appropriate therapy.
How to perform tests after a tick bite? - in detail
After a tick attachment, a systematic diagnostic approach is essential to detect early infection and guide treatment. Begin with a thorough history: note the date of the bite, geographic region, duration of attachment, and any visible engorgement. Conduct a complete skin examination, focusing on the bite site for erythema, a central necrotic area, or expanding rash.
The following investigations should be ordered based on risk assessment:
- Serologic testing for Borrelia burgdorferi – enzyme‑linked immunosorbent assay (ELISA) followed by immunoblot confirmation if positive. Perform the first sample at least two weeks after exposure; a second convalescent sample after four weeks helps identify seroconversion.
- Polymerase chain reaction (PCR) for tick‑borne pathogens – useful for detecting DNA of Borrelia, Anaplasma, Ehrlichia, and Babesia in blood or tissue when clinical suspicion is high and serology may be negative early.
- Complete blood count (CBC) with differential – leukocytosis or lymphopenia can indicate systemic infection; eosinophilia may suggest a co‑infection.
- Comprehensive metabolic panel – evaluate liver and renal function, which may be affected by certain tick‑borne diseases.
- Blood smear – examine for intra‑erythrocytic parasites (Babesia) if febrile illness occurs.
- Urinalysis – screen for proteinuria or hematuria that can accompany Lyme nephritis.
- Imaging studies – consider MRI of the brain or joints if neurological or arthritic symptoms develop; chest radiography may be indicated for respiratory involvement in Rocky Mountain spotted fever.
If the bite occurred in an area endemic for specific agents (e.g., Powassan virus, tularemia), add targeted testing such as viral PCR or culture for Francisella tularensis. Repeat serologic panels at 4–6 weeks when initial results are negative but clinical suspicion persists.
Document all findings, test dates, and results in the patient record. Prompt interpretation of laboratory data, combined with clinical signs, enables early antimicrobial therapy and reduces the risk of complications.