CHIT1 and nasopharyngeal carcinoma: This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C–C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C.