Abstract: Apparatus for using electrochemical noise analysis to assess the coating upon a conductive substrate comprises an electrolyte-containing cell, a witness electrode, a reference electrode and a working conductor. The electrolyte-containing cell is securely coupled with the coated conductive substrate so that the electrolyte is contiguous with a coated area of the metal substrate, which is demarcated by an electrolytic contact-permitting aperture in the electrolyte-containing cell. The witness electrode contacts the electrolyte and connects to an ammeter. The reference electrode contacts the electrolyte and connects to a voltmeter. Via the working conductor, the ammeter and the voltmeter each connect to a noncoated region of the metal substrate. The conductive substrate's coated area which contacts the electrolyte effectively represents a working electrode. Practice “in the field” is possible relative to coated conductive substrates associated with diverse entities.