Red Cell Lysis Buffer Application Versus Conventional Sample Processing in EUS-FNB

Red Cell Lysis Buffer Application Versus Conventional Sample Processing in Endoscopic Ultrasonography (EUS)-Guided Biopsy for Solid Pancreatic Lesions

The goal of this clinical trial is to evaluate the application of red cell lysis buffer (RCLB) versus conventional sample processing in endoscopic ultrasonography (EUS)-guided biopsy for solid pancreatic lesions. The main questions it aims to answer are: whether the application of red cell lysis buffer improves histological tissue quality by decreasing blood contamination. Participants with solid pancreatic lesions who needs histological diagnosis will receive EUS-guided biopsy. The obtained specimens will be processed by RCLB and conventional formalin solution. Researchers will compare the blood contamination score of specimens in RCLB group with the conventional group see if the blood contamination can be improved.

Patients assigned to this group will receive EUS-FNB as routine. The obtained tissue will be processed with red cell lysis buffer and underwent histological evaluation.

Patients assigned to this group will receive EUS-FNB as routine. The obtained tissue will be fixed with formalin as usual and underwent histological evaluation.

The tissue is lysed with 50% concentration of RCLB for 15 min on a shaking device. If the lysis is judged to be insufficient, it can be repeated one more time. Finally, the treated tissue will be fixed with 10% formalin.

Microscopic blood contamination is assessed by grading the percentage of the area of the blood cells in the entire ×40 field of view (score 3, < 25 %; score 2, 25 % - 50%; score 1, > 50 %; score 0, no material)

The tissue integrity on histological analysis was also graded into 3 levels: Grade A, existing core tissue (defined as an architecturally intact piece of tissue with a long axis measuring at least 550 μm), which can clearly characterize the lesion, and is sufficient for diagnosis; Grade B, existing core fragments, which does not meet the criteria for architecturally intact histology, but can still yield a diagnosis based on cell morphology; and Grade C, no lesion tissue found, and a diagnosis cannot be made based on the sample.

Macroscopic visual quality of histopathological samples is assessed by grading the percentage of red (blood) component ejected from the needle on a glass slide (score 4, white tissue only; score 3, < 25 %; score 2, 25 % - 50%; score 1, > 50 %; score 0, no material).

MVC (macroscopically visible core), defined as a measurable whitish sample. After collecting the MVCs scattered in the samples, the samples were aligned using a needle, and their length was measured using a ruler.

Diagnostic accuracy was calculated as the proportion of true positive and true negative in all evaluated cases

Immunohistochemical assessment: a. Detect whether the expression of membrane proteins is the same in treated and untreated specimens from the additional 3 groups of patients. b. Grading the percentage of the area of non-specific staining of erythrocytes in the entire ×40 field of view. Score of 3, non-specific staining present in < 25% of slides; score of 2, non-specific staining present in 25% - 50% of slides; score of 1, non-specific staining is present in > - 50% of slides

Inclusion Criteria: 18 to 80 years old; Solid pancreatic lesions confirmed by clinical and CT/MRI/ PET imaging. Signed written informed consent Exclusion Criteria: Contraindication of EUS-guide procedure or technical infeasibility (e.g.,coagulation disorder, anatomical changes, large vessels along the puncture path) Pregnant Patient is enrolled in any other clinical protocol or investigational trial

Department of Gastroenterology, Changhai Hospital, Naval Medical University (Second Military Medical University), Shanghai, China.