Oilphase, a Schlumberger company, has developed and successfully tested a novel Single-phase Sampling Technology (SST), which is in use worldwide. In this system, the collected reservoir fluid pressure is maintained at or above reservoir pressure during retrieval by the release of a pre-set nitrogen charge. Subsequent to collecting the single-phase reservoir fluid, experiments were conducted in the laboratory to demonstrate the importance of SST. Results indicate that the onset of asphaltene flocculation pressure indeed varies with the amount of asphaltene content in the reservoir fluid. The collection of a non-representative reservoir fluid sample may carry a non-representative asphaltene amount due to irreversible precipitation, and hence, result in characterization of a non-representative asphaltene flocculation onset. Therefore, asphaltene characterization on a nonrepresentative reservoir fluid sample will lead to either over- or under-design of the production system.