Diagnostic utility of HFLC% and IG% for acute Pancreatitis - A retrospective Case-Control study

Objective: To evaluate the occurrence, development and outcome value of hyperfluorescent lymphocyte percentage (HFLC%) and immature granulocyte percentage (IG%) for acute pancreatitis (AP). Methods: The laboratory data collected from 1533 patients diagnosed with AP between August 2018 and August 2022 were retrospectively analyzed. The patients were classified into mild acute pancreatitis (MAP) and non-mild acute pancreatitis (Non-MAP) groups; non-MAP groups were additionally subgrouped based on HFLC% at day 7. White blood cells (WBC), HFLC%, and IG% were examined from day 1 (baseline) to day 14 post-admission using Sysmex XN Series Hematology Analyzers. C-reactive protein (CRP), serum amylase (AMY), and lipase (LPS) were detected by Beckman AU5800. Results: A total of 623 patients were finally included in the study [MAP group (n = 358) and Non-MAP group (n = 265)]. WBC, IG%, and CRP were higher in the Non-MAP group from day 1 to day 12 (all P<0.05). The HFLC% was not statistically significant from day 1 to day 6; yet, it increased on day 6 and 7 in the Non-MAP group. We divided patients in the Non-MAP group with complete data(101 patients) into HFLC% >= 2.9 %(31 patients) and HFLC% < 2.9 %(70 patients) according to the threshold of 7th day HFLC%. WBC, HFLC%, IG%, and CRP effectively predicted the progression of MAP to Non-MAP (all P < 0.001). HFLC% was the most obvious value, followed by CRP and IG%. Combined with HFLC%, IG%,CRP and WBC in day7, the ROC analysis showed that the area under ROC curve of the combined indicators was the largest (AUC = 0.912, P < 0.001) and had higher sensitivity and specificity than single-item assessment of AP outcomes(P < 0.05). HFLC% < 2.9 %, IG% > 1.7 %, CRP >28.66 mg/L, and WBC >9.24 x 10(9)/L indicated the possibility of AP disease aggravation. Also, HFLC% <2.9 % was directly associated with infection, SIRS, APPACHII grade, and ICU admission (all P < 0.05). In non-MAP there was a significant negative correlation between HFLC% and APACHE-II score (r(s) = -0.312, P = 0.023). Conclusion: HFLC% <2.9 % on 7th day was directly indicated more infection, systemic inflammatory response syndrome(SIRS), higher APPACH II grade and ICU admission. HFLC% may be an independent laboratory marker for prognosis in AP. Combining HFLC% with IG%, CRP, and WBC helps evaluate AP patients' disease development and outcome.