DIRECT DETERMINATION OF CRYPTOCOCCAL ANTIGEN IN TRANSTHORACIC NEEDLE ASPIRATE FOR DIAGNOSIS OF PULMONARY CRYPTOCOCCOSIS

Pulmonary cryptococcosis causes significant morbidity and mortality in immunocompromised patients, Definitive diagnosis of pu!monary cryptoc occosis is usually difficult. The use of direct determination of crypt ococcal antigen in transthoracic needle aspirate to diagnose pulmonary cryptococcosis was investigated, Over a 2-year period, we studied a t otal of 41 patients with respiratory symptoms and pulmonary infiltrate s of unknown etiology who were suspected of having pulmonary cryptococ cosis, Twenty-two patients were immunocompetent patients and 19 patien ts were immunocompromised, A diagnosis of pulmonary cryptococcosis was based on cytological examination, culture for Cryptococcus neoformans , histopathologic examination, and clinical response to antifungal the rapy, All patients underwent chest ultrasound and ultrasound-guided pe rcutaneous transthoracic needle aspiration to obtain specimens for cry ptococcal antigen determination, The presence of cryptococcal antigen was determined by the latex agglutination system (CALAS; Meridian Diag nostics, Cincinnati, Ohio). An antigen titer equal to or greater than 1:8 was considered positive, The specimens were also sent for cytologi cal examination, fungal culture, and/or histopathologic examination, A final diagnosis of pulmonary cryptococcosis was made in eight patient s, Direct determinations of cryptococcal antigen in lung aspirate were positive in all eight patients with pulmonary cryptococcosis (100% se nsitivity, 97% specificity, a positive predictive value of 89%, and ne gative value of 100%), and there was only one false-positive in noncry ptococcosis patients, The diagnostic accuracy was 97.5%. Serum cryptoc occal antigen was positive in only three patients with pulmonary crypt ococcosis (sensitivity, 37.5%), This study showed that direct measurem ent of cryptococcal antigen in lung aspirate can be a rapid and useful test for diagnosis of pulmonary cryptococcosis.