**3. Microbiological diagnosis: Pros and cons of different approaches**

Adequate microbiological procedures must reflect the special character of periprosthetic infections in order to identify the causative agents accurately. Although largely interdependent, eight issues which may influence the significance of microbiologic testing are addressed separately in the following: i) patient-specific factors, ii) the sample character, iii) the logistic interface between the clinic and the laboratory, iv) the method of sample processing, v) the means of identification, vi) the culture conditions, vii) the means of discriminating between infection and contamination, and viii) the stage at which sample materials are drawn (pre-operatively versus intra-operatively).
