Having a good methodology for establishing truth of diagnosis would be invaluable to researchers in radiology. A protocol to verify the truth of diagnosis of clinical images to be used in radiologic research has been proposed that specifies six classes, depending on how the diagnosis is verified. In this paper it was evaluated. The protocol was applied to sixty-nine liver-spleen scans. Using five of the possible six classes of the protocol, 42% of the scans were verifiable. Twenty-eight per cent of the cases could be verified by non-physicians using the first four classes of the protocol. In 96% of a sample of these cases, their diagnosis matched that of the physicians. Radiologists are needed for the last two classes. However, using three radiologists to investigate Class V protocol procedures only eight (16%) more cases were clearly classifiable. Class VI was not investigated. The protocol met its objectives of reducing physician involvement and developing a detailed methodology. The difficulties inherent in verification of diagnosis are also discussed, and suggestions for improving the protocol are proposed.