The levels of hydrogen peroxide (H2O2) in human blood is of great relevance since it has emerged as an important signalling molecule, an indicator of oxidative stress, in a variety of disease states. Fast and reliable measurement of H2O2 levels in the blood, however, continues to remain a challenge. We have developed a method employing an integrated microfluidic device for rapid measurement of H2O2 in human blood, based on laser-induced fluorescence measurement. Our study delineates some of the critical factors that affect the measurement accuracy – we found that the blood cells and soluble proteins can significantly alter the native H2O2 levels in the time interval between sample withdrawal and detection. We demonstrate rapid measurement of H2O2 in plasma in the concentration range of 0 – 49 µM, with a limit of detection of 0.05 µM, the sensitivity of 0.60 µM-1, and detection time of 15 min; the device is amenable to the real-time measurement of H2O2 in the patient’s blood. The availability of this device at the point of care will have relevance in understanding the role of H2O2 in health and disease.