Diagnostic value of the combinations of bronchoalveolar lavage fluid pathogen detection and cryptococcal antigen test in pulmonary cryptococcosis

Abstract

Objective: To evaluate the diagnostic value of bronchoalveolar lavage fluid pathogen detection combined with cryptococcal antigen test(CrAg) for pulmonary cryptococcosis(PC). Methods: A retrospective case analysis was performed on non-acquired immunodeficiency syndrome patients admitted to Ninghai First Hospital for suspected PC from January 2018 to December 2019. Fifty-nine patients were included. Sixteen cases (8 males and 8 females) were diagnosed with PC, aged from 18 to 76 years[an average age of (52±14) years], while 43 cases were diagnosed as having Non-PC. All patients had undergone both serum CrAg test and BALF pathogen detection(cultures and direct examination) combined with BALF-CrAg test. The sensitivity and specificity of the combined method of BALF was evaluated, and a parallel comparison of the diagnostic efficiencies of the two methods were made. Results: Of the 16 confirmed PC cases, serum CrAg tests were positive in 11 and negative in 5 cases, while the combined method showed that 14 were positive and 2 were negative. Compared with the clinical final diagnosis, the sensitivity, specificity, positive predictive value and negative predictive value showed that the serum CrAg tests were 68.8% (11/16), 97.7% (42/43), 91.7% (11/12), 89.3% (42/47) respectively, versus 87.5% (14/16), 100.0% (43/43), 100% (14/14), 95.6% (43/45) by the combined method of BALF. The results displayed no statistical difference between the two diagnostic methods (P =1.000). Among the 5 initially serum CrAg-negative cases, 4 were later confirmed as proven PC via the combined method of BALF and the other one by percutaneous lung biopsy. Conclusion: The combined method of BALF pathogen detection with BALF-CrAg showed a similar statistical efficiency rate for diagnosing pulmonary cryptococcosis compared with serum CrAg tests. It may serve as an efficient diagnosis method for PC cases with negative serum CrAg tests.