Synopsis
Apply the sampling-before-treatment principle without turning it into a dangerous delay, select the right target and technique, preserve laboratory value, and make explicit decisions for sepsis, anticoagulation and difficult anatomy.
- The principle is conditional: stable patient plus promptly accessible target equals aspiration before antibiotics; instability or unsafe delay equals blood cultures, immediate treatment and source control.
- Define the question and compartment before inserting a needle: native joint, prosthetic joint, bursa, soft-tissue abscess, bone, paraspinal collection and postoperative space require different routes and tests.
- Use sterile technique through intact skin where possible, avoid traversing cellulitis or a tumour plane, use ultrasound or CT for deep targets and record site, side, time and prior antibiotics.
Key red flags
Shock, organ dysfunction, high-risk sepsis or rapidly worsening infection requires antibiotics after rapid blood cultures even when image-guided or operative aspiration is not immediately available.
Investigation priorities
Decide whether sampling can safely precede treatment.
Management branches
Infection is plausible, physiology is stable and the target can be accessed promptly.
- Document observations, target, planned tests, prior antibiotics and the latest acceptable aspiration time.
- Use sterile image-guided or operative technique through the safest anatomical route and collect enough correctly labelled material.
Key medicines
Post-aspiration empirical antimicrobial therapyImmediately after adequate source and indicated blood cultures in a stable adult, administer the full agent, route, dose and interval in the relevant local native-joint, bone, implant or abscess protocol; record a specific review at preliminary culture availability.
Immediate therapy when sampling delay is unsafeIn high-risk sepsis or rapidly threatened tissue, obtain rapidly available blood cultures and give the full intravenous sepsis and source-specific regimen without waiting for delayed image-guided aspiration; still collect deep material at the earliest drainage or debridement.