Table 3.

Cyst fluid analysis

	Cyst fluid analysis
European guidelines[28]	Cyst fluid CEA with cytology, or KRAS/GNAS mutation analysis for differentiating IPMN or MCN from other pancreatic cysts
American College of Gastroenterology (ACG) guidelines[30]	Cyst fluid CEA to differentiate IPMNs and MCNs from other cyst types
	Cyst fluid cytology to assess for HGD or pancreatic cancer when imaging features are alone insufficient for surgery
	Molecular markers like KRAS or GNAS mutations can help identify IPMNs or MCNs when the diagnosis is not clear
American Gastroenterology Association (AGA) guidelines[31]	Cyst fluid cytology is recommended for the evaluation of high-risk features on imaging. The role of molecular markers is not clear and further research is needed
Revised IAP 2017 guidelines[32]	Cyst fluid CEA can distinguish mucinous from non-mucinous cysts. CEA level ≥ 192-200 ng/mL is 80% accurate for the diagnosis of mucinous cyst[38,45]
	Cyst fluid cytology can be diagnostic but sometimes limited by scant cellularity[43,44]
	Cyst fluid amylase can differentiate benign from malignant MCN and amylase levels are higher in pseudocysts than non-pseudocysts[45]. The role of molecular markers like KRAS and GNAS mutations is still evolving
American College of Radiology guidelines[33]	Cyst fluid CEA ≥ 192 ng/mL can help identify a mucinous cyst[46]
	Cyst fluid amylase > 250 IU/L suggests pseudocyst[11]
	KRAS and GNAS molecular markers can help differentiate mucinous from non-mucinous cysts[47]
	Cyst cytology can identify dysplastic cells

CEA: Carcinoembryonic antigen; IPMN: Intraductal papillary mucinous neoplasm; MCN: Mucinous cystic neoplasm; GNAS: Guanine nucleotide-binding protein; KRAS: Kirsten rat sarcoma viral oncogene homolog; HGD: High-grade dysplasia.