The PBS IIc SELDI-TOF mass spectrometer reader is a laser desorption ionization time of flight mass spectrometer equipped with a pulsed ultraviolet nitrogen laser source. When the laser activates the bound serum biomarkers on the chip surface, the biomarkers become desorbed and ionized. Ionized molecules fly along the mass spectrometer to the ion detector in a time of flight manner according to their mass over charge ratio (m/z). When the ion signal is detected in the ion detector, signal processing is accomplished by high-speed analog-to-digital converter linking to a computer. Detected protein biomarkers are displayed in spectral, map or gel view formats by the Ciphergen ProteinChip software 3.0.2. The following steps show how the chips are read in the mass spectrometer.