This document is intended to clarify the procedure for accurate measurements of LED and SSL (Solid State Lighting) products by means of an integrating sphere. In perspective of CIE 127: 2007 recommendations, the entire procedure including calibration, absorption correction and led measurements is listed. Special attention is given to the enhancements of the calibration procedure with an Admesy tungsten broadband reference standard compared to the conventional calibration procedure. At last a number of general remarks concerning LED measurements are provided to ensure accurate and repeatable LED measurements.