Creep experiments have been applied to probe the zero-shear viscosity, eta(0), of polyethylene chains directly and precisely in a constant-stress rheometer at 190 degrees C. Such experiments, when combined with precise measurements of the weight-average molecular weight, M-w, calibrated relative to linear chains of high-density polyethylene, are shown to provide a very sensitive approach to detect low levels (0.005 branches per 1000 carbons) of long-chain branching (LCB). This detection limit is shown to be insensitive to whether the molecular weight distribution (MWD) breadth, M-w/M-nr rises from about two to ten. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 636-646, 2011