A variety of immunologic techniques have been introduced during the past few years. Many of these techniques are being applied to clinical specimens in an attempt to help the practicing veterinarian make a diagnosis. The introduction of new techniques requires extensive testing with clinically normal and diseased patients. It is essential for the practicing veterinarian to understand that the techniques available for the detection of immunologic disorders in the dog and cat are not routine diagnostic procedures and that adequate information has not been developed for any of the techniques described to assure the clinical significance of either positive or negative results (Table 3). This should not discourage the practitioner from submitting samples, but should encourage him or her to question the significance of those results and to attempt to correlate them with history and clinical signs before arriving at a final diagnosis.