Where should blood be taken after a tick bite? - briefly
Draw blood from a peripheral vein, most commonly the antecubital fossa, to obtain a sample after a tick attachment. This location yields adequate volume while minimizing contamination risk.
Where should blood be taken after a tick bite? - in detail
Blood should be drawn from a site distant from the tick attachment to avoid local inflammation and potential contamination. The preferred venipuncture location is the median cubital vein in the antecubital fossa, because it is large, superficial, and easily accessed. If that vein is unsuitable, the cephalic or basilic veins on the same arm are acceptable alternatives. The arm opposite the bite should be selected whenever possible.
Key considerations:
- Distance from the bite – at least 5 cm away; preferably the contralateral limb.
- Vein size and stability – choose a vein that allows smooth needle insertion and adequate blood flow.
- Patient comfort – avoid areas with swelling, erythema, or tenderness.
- Infection control – use aseptic technique; disinfect the skin with an appropriate antiseptic before puncture.
Laboratory tests commonly ordered after a tick exposure include:
- Complete blood count (CBC) – assesses for anemia, leukocytosis, or thrombocytopenia that may accompany infection.
- Serologic testing for Borrelia burgdorferi – enzyme‑linked immunosorbent assay (ELISA) followed by Western blot if positive; initial test is usually performed 2–4 weeks post‑exposure.
- C‑reactive protein (CRP) or erythrocyte sedimentation rate (ESR) – markers of systemic inflammation.
- Liver function panel – monitors hepatic involvement in severe tick‑borne illnesses.
- Renal panel – evaluates kidney function, especially if hemolysis or nephritis is suspected.
If immediate results are needed, a capillary finger‑stick may be used for rapid point‑of‑care tests, but venous sampling remains the standard for comprehensive serology and complete panels. Follow‑up blood draws are typically scheduled at 2‑6 weeks to confirm seroconversion or to monitor treatment response.