CORRECT TEST SELECTION: a test must have the potential to alter patient management and have the specificity and sensitivity appropriate to the pretest probability of disease.CORRECT DYNAMIC TEST PROCEDURE: dynamic tests may assist diagnosis and protocols must be readily available.CORRECT PATIENT PREPARATION: fasting, or other patient preparation, may reduce variability. Clear communication, to both patients and staff, of any such requirements is essential.CORRECT SAMPLE COLLECTION: the tube type (for blood) or container (for urine) must be appropriate for the analyte; there must be sufficient volume, avoidance of venous stasis, contaminants and haemolysis; and adequate labelling.CORRECT SAMPLE HANDLING: the time and temperature before and after separation, and the centrifugation and separation procedures, must be suitable for the analyte. Accept/reject criteria must be defined.Methods require thorough evaluation of patient-related pre-analytical factors, and quantification of the effects of time, temperature, haemolysis, anticoagulant type and minimum allowable volume on sample suitability.