Performance of rapid on-site evaluation of touch imprints of lung tissue biopsies for the diagnosis of pulmonary cryptococcosis in patients without HIV infection.

Background And Objective: The diagnosis of pulmonary cryptococcosis depends on serum testing, histopathology and mycological culture; there are few studies on touch imprints of lung tissue biopsies for the diagnosis of pulmonary cryptococcosis in patients without HIV infection. The purpose of the current study was to investigate the accuracy and timeliness of on-site touch imprint cytology in the diagnosis of pulmonary cryptococcosis during CT-guided percutaneous lung biopsy.

Methods: We retrospectively analysed the diagnosis and treatment of 56 patients with final proof of pulmonary cryptococcosis through histopathology and culture or surgical resection from September 2015 to February 2021. Diagnostic methods and treatment and the turnaround time for diagnosis were analysed.

Results: The sensitivity of rapid on-site evaluation was 89.3%, and the sensitivity of serology, histopathology and mycological culture was 53.6%, 91.1% and 61.5%, respectively, compared with the final diagnosis. The average turnaround time to diagnose pulmonary cryptococcosis by on-site touch imprint cytology was 8.3 ± 0.9 min, which was significantly faster than serum testing, histopathology and mycological culture.

Conclusion: On-site touch imprint cytology showed good sensitivity and timeliness in the diagnosis of pulmonary cryptococcosis. In addition, it contributed to the triage of biopsies based on the preliminary diagnosis. On-site touch imprint cytology should be applied and promoted in the diagnosis of pulmonary cryptococcosis during biopsy.