Drilling of horizontal wells with multi-stage hydraulic fracturing (MFHW) is one of the most common solutions in the development of low-permeable oil and gas reservoirs. At the same time, the estimation of the well and reservoir parameters by well test analysis is complicated due to long time response to the radial flow regime. It is possible to eliminate uncertainty dealt with the absence of radial flow response by using data from the early radial regime that occurs at early times of pressure buildup. However, its appearance is only possible if the distance between the parallel fractures is much larger than the fracture half-lengths, which is not usual in practice. At the same time, MFHW demonstrate a complex buildup behavior due to fracture interference. By analytical and numerical simulations it is shown that the early time buildup behavior depends on duration of well production before shut-in. This behavior is similar to the buildup of a vertical well near the sealed boundary. For short production times, a radial-like regime may appear at early buildup times caused by elliptical flow around the fractures. The consistency of this regime and the relation of the pressure derivative plateau level to the parameters of the elliptical flow are justified. An empirical formula of sufficient accuracy has been obtained for reservoir transmissibility (flow capacity). This formula is applicable for the most common range of parameter values of the MFHW. These results open up new opportunities for reliable assessment of the well and reservoir parameters from well tests in MFHW in low-permeability reservoirs, including new wells or wells restarted after a long inactive period.