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Decreased particle concentrations in vehicle exhaust due to the use of particulate traps pose new challenges to particle measurement methods in terms of sensitivity and repeatability. In the present paper nanoparticle measurement methods are compared to gravimetric and coulometric analysis of filter samples from CVS sampling with special attention to the consequences for the measurement of DPF efficiency. Repeatability and sensitivity of the methods are assessed, and the influence of dilution and sampling is investigated. It is shown that the repeatability of nanoparticle measurement methods is of the same order as that of PM measurement. In terms of sensitivity, nanoparticle methods are by three orders of magnitude better than today's PM and EC measurement. This provides a much better signal-to-noise ratio, especially when particle emissions are very low.