What is the status of the Kveim test in the diagnosis of sarcoidosis? Where can I get the antigen? What is the specificity and sensitivity of the test?
—Lester N. Ploss, MD, Freeport, N.Y.
The Kveim-Siltzbach test (KST) consists of injecting the Kveim reagent, a particulate suspension prepared from granulomatous splenic tissue of a patient with sarcoidosis, into the skin of a person with suspected sarcoidosis. Approximately 50%-80% of patients with sarcoidosis have a positive reaction and develop noncaseating granulomas in the injection site as seen on skin biopsy four to six weeks later. The false-positive rate has been quoted at 1%-5%, although most of the underlying data are more than 40 years old.
Once a tool for the noninvasive diagnosis of sarcoidosis, the KST is no longer used clinically. The reasons behind this discontinuation are the availability of transbronchial biopsy, difficulty obtaining a clinically validated KST reagent, and the possibility of disease transmission with the injection of human tissue. The Kveim reaction is still not fully understood, and the active component of what causes the antigenic response has not been identified. As such, it is still used for research purposes to better understand the etiology of sarcoidosis (Clin Chest Med. 2008;29:365-377).
—Susan Kashaf, MD, MPH (132-9)