Validation of biochemical reports must be fast and clinically accurate to be of assistance to clinicians. Considerable skill is required to analyse the consistency of different data in the report and to consider influences on the data. When performed throughout the day, such analysis is time-consuming and uncertain. We therefore decided to use a computer-assisted validation system, Valab-Biochem. Its decisions result from a decision tree based primarily on the intrinsic consistency of the data, validation ranges and patients' sex, age and hospital ward. Three hundred randomly chosen reports were simultaneously submitted to Valab-Biochem and to five biologists in order to analyse the computer's findings. The sensitivity of Valab-Biochem was 80% compared to biologists' consensus decision, which was taken as the gold standard. The specificity was 78%. This system provided autonomous assessment of the reports and could be used as an initial screen to assist biologists and focus attention on potentially inconsistent reports.