Clopidogrel pretreatment significantly improves outcome in patients undergoing percutaneous coronary intervention (PCI), but it is not well established if the ad hoc loading of clopidogrel before the PCI and after coronary angiography is efficient and safe for the patient. According to the results of PRAGUE-8 and ARMYDA-5 PRELOAD trials, in-lab loading with 600mg clopidogrel might be safe and effective alternative to pre-treatment given several hours before diagnostic angiography or PCI. Still there is concern about adequate platelet inhibition, which can be overcome either with new loading scenarios or introducing more potent, more predictable, faster onset antiplatelet drugs, such as prasugrel and ticagrelor. Although increasing evidence suggests a link between residual platelet reactivity and adverse clinical outcomes, large scale clinical trials are still necessary to determine whether changes in therapy based on results of platelet function testing improve clinical outcomes, and thus will determine whether broader use of platelet function testing in clinical practice is warranted.