2.2 Specimen collection and processing
All bronchoscopies were performed by the same experienced
bronchoscopist. Each patient was locally anesthetized with 2%
lidocaine, then an ultrathin bronchoscope (BF-typ XP260F; Olympus:
external diameter, 2.8 mm; channel diameter, 1.2 mm) was navigated to
the target bronchus as far as possible using the VBN system (Direct Path
1.0). TBLB, BB and bronchoalveolar lavage (BAL) of peripheral lesions
were performed in sequence in all subjects. On each patient, TBLB was
performed at first, meanwhile ROSE were performed during the examination
to determine whether the sample was sufficient for diagnosis. Then BB
was performed using a protective needle brush and BALF specimens were
obtained after brushing samples. The specimens obtained with TBLB and
BAL were separately sent to the clinical microbiology laboratory for
culture and sequencing company for mNGS, the TBLB specimens were also
sent to the pathological laboratory for pathological examination. The
protective needle tips were cut with sterile scissors and placed in a 2
ml sterile microcentrifuge tubes containing 1 ml of sterile saline and
sent to the sequencing company for mNGS.