title: Optimizing the multimodal approach to pancreatic cyst fluid diagnosis: developing a volume-based triage protocol.
abstract: BACKGROUND
  The objective of this study was to develop a triage algorithm to optimize diagnostic yield from cytology, carcinoembryonic antigen (CEA), and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) testing on different components of a single pancreatic cyst fluid specimen. The authors also sought to determine whether cell block supernatant was suitable for CEA and KRAS testing.
  
  
  METHODS
  Fifty-four pancreatic cysts were triaged according to a volume-dependent protocol to generate fluid (neat and supernatant) and cell block specimens for cytology, comparative CEA, and KRAS testing. Follow-up histology, diagnostic cytology, or a combined clinicopathologic interpretation was recorded as the final diagnosis.
  
  
  RESULTS
  There were 26 mucinous cystic lesions and 28 nonmucinous cystic lesions with volumes ranging from 0.3 mL to 55 mL. Testing different components of the specimens (cell block, neat, and/or supernatant) enabled all laboratory investigations to be performed on 50 of 54 cyst fluids (92.6%). Interpretive concordance was observed in 17 of 17 cases (100%) and in 35 of 40 cases (87.5%) that had multiple components tested for CEA and KRAS mutations, respectively. An elevated CEA level (>192 ng/mL) was the most sensitive test for the detection of a mucinous cystic lesion (62.5%) versus KRAS mutation (56%) and "positive" cytology (61.5%). KRAS mutations were identified in 2 of 25 mucinous cystic lesions (8%) in which cytology and CEA levels were not contributory.
  
  
  CONCLUSIONS
  A volume-based protocol using different components of the specimen was able to optimize diagnostic yield in pancreatic cyst fluids. KRAS mutation testing increased diagnostic yield when combined with cytology and CEA analysis. The current results demonstrated that supernatant is comparable to neat fluid and cell block material for CEA and KRAS testing.
authors.affiliation: PathWest Laboratory Medicine, Queen Elizabeth II Medical Center, Nedlands, Western Australia, Australia. ming.chai@health.wa.gov.au
authors.forename: Siaw Ming
authors.initials: SM
authors.lastname: Chai
authors.forename: Karl
authors.initials: K
authors.lastname: Herba
authors.forename: M Priyanthi
authors.initials: MP
authors.lastname: Kumarasinghe
authors.forename: W Bastiaan
authors.initials: WB
authors.lastname: de Boer
authors.forename: Benhur
authors.initials: B
authors.lastname: Amanuel
authors.forename: Fabienne
authors.initials: F
authors.lastname: Grieu-Iacopetta
authors.forename: Ee Mun
authors.initials: EM
authors.lastname: Lim
authors.forename: Dev
authors.initials: D
authors.lastname: Segarajasingam
authors.forename: Ian
authors.initials: I
authors.lastname: Yusoff
authors.forename: Chris
authors.initials: C
authors.lastname: Choo
authors.forename: Felicity
authors.initials: F
authors.lastname: Frost
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001315:Australia; D015415:Biomarkers / Q000032:analysis; D044963:Biopsy, Fine-Needle / Q000379:methods; D002272:Carcinoembryonic Antigen / Q000032:analysis* / Q000235:genetics; D015331:Cohort Studies; D020420:Cyst Fluid / Q000737:chemistry* / Q000166:cytology* / Q000000981:diagnostic imaging; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D019160:Endosonography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010181:Pancreatic Cyst / Q000473:pathology* / Q000601:surgery; D011300:Preoperative Care / Q000379:methods; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012680:Sensitivity and Specificity; D014218:Triage; D018631:ras Proteins / Q000032:analysis / Q000235:genetics*
chemical_list: D015415:Biomarkers; D002272:Carcinoembryonic Antigen; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins